[🍒][libc++] Rename include/support to include/__support

[ldionne]

Summary

We do ship those headers, so the directory name should not be something
that can potentially conflict with user-defined directories.

This is a cherry-pick of b51756819a85563ae063e98eeb3d6af8e44c8f64.

[ldionne]

This is a cherry-pick from main to release/12.x. I think that is fairly important, because we now ship the support/ directory alongside the libc++ headers, and I am concerned that this could clash with user-provided support/ directories on users' header search paths.

[tstellar]

Please go ahead and merge this to the release/12.x branch.

[ldionne]

395ef8d5c67905646b72dd5ef2d8eb60cabb8634

libcxx/include/CMakeLists.txt

set(files
   stdint.h
   stdio.h
   stdlib.h
   streambuf
   string
   string.h
   string_view
   strstream
-  support/android/locale_bionic.h
-  support/fuchsia/xlocale.h
-  support/ibm/limits.h
-  support/ibm/locale_mgmt_aix.h
-  support/ibm/nanosleep.h
-  support/ibm/support.h
-  support/ibm/xlocale.h
-  support/musl/xlocale.h
-  support/newlib/xlocale.h
-  support/nuttx/xlocale.h
-  support/openbsd/xlocale.h
-  support/solaris/floatingpoint.h
-  support/solaris/wchar.h
-  support/solaris/xlocale.h
-  support/win32/limits_msvc_win32.h
-  support/win32/locale_win32.h
-  support/xlocale/__nop_locale_mgmt.h
-  support/xlocale/__posix_l_fallback.h
-  support/xlocale/__strtonum_fallback.h
+  __support/android/locale_bionic.h
+  __support/fuchsia/xlocale.h
+  __support/ibm/limits.h
+  __support/ibm/locale_mgmt_aix.h
+  __support/ibm/nanosleep.h
+  __support/ibm/support.h
+  __support/ibm/xlocale.h
+  __support/musl/xlocale.h
+  __support/newlib/xlocale.h
+  __support/nuttx/xlocale.h
+  __support/openbsd/xlocale.h
+  __support/solaris/floatingpoint.h
+  __support/solaris/wchar.h
+  __support/solaris/xlocale.h
+  __support/win32/limits_msvc_win32.h
+  __support/win32/locale_win32.h
+  __support/xlocale/__nop_locale_mgmt.h
+  __support/xlocale/__posix_l_fallback.h
+  __support/xlocale/__strtonum_fallback.h
   system_error
   tgmath.h
   thread
   tuple
   type_traits
   typeindex
   typeinfo
   unordered_map

libcxx/include/__locale

 #include <memory>
 #include <utility>
 #include <mutex>
 #include <cstdint>
 #include <cctype>
 #include <locale.h>
 #if defined(_LIBCPP_MSVCRT_LIKE)
 # include <cstring>
-# include <support/win32/locale_win32.h>
+# include <__support/win32/locale_win32.h>
 #elif defined(__NuttX__)
-# include <support/nuttx/xlocale.h>
+# include <__support/nuttx/xlocale.h>
 #elif defined(_AIX) || defined(__MVS__)
-# include <support/ibm/xlocale.h>
+# include <__support/ibm/xlocale.h>
 #elif defined(__ANDROID__)
-# include <support/android/locale_bionic.h>
+# include <__support/android/locale_bionic.h>
 #elif defined(__sun__)
 # include <xlocale.h>
-# include <support/solaris/xlocale.h>
+# include <__support/solaris/xlocale.h>
 #elif defined(_NEWLIB_VERSION)
-# include <support/newlib/xlocale.h>
+# include <__support/newlib/xlocale.h>
 #elif defined(__OpenBSD__)
-# include <support/openbsd/xlocale.h>
+# include <__support/openbsd/xlocale.h>
 #elif (defined(__APPLE__)      || defined(__FreeBSD__) \
     || defined(__EMSCRIPTEN__) || defined(__IBMCPP__))
 # include <xlocale.h>
 #elif defined(__Fuchsia__)
-# include <support/fuchsia/xlocale.h>
+# include <__support/fuchsia/xlocale.h>
 #elif defined(__wasi__)
 // WASI libc uses musl's locales support.
-# include <support/musl/xlocale.h>
+# include <__support/musl/xlocale.h>
 #elif defined(_LIBCPP_HAS_MUSL_LIBC)
-# include <support/musl/xlocale.h>
+# include <__support/musl/xlocale.h>
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 

libcxx/include/__support/android/locale_bionic.h

 // -*- C++ -*-
-//===------------------- support/android/locale_bionic.h ------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_ANDROID_LOCALE_BIONIC_H

 }
 #endif
 
 #if defined(__ANDROID__)
 
 #include <android/api-level.h>
 #include <android/ndk-version.h>
 #if __ANDROID_API__ < 21
-#include <support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__posix_l_fallback.h>
 #endif
 // In NDK versions later than 16, locale-aware functions are provided by
 // legacy_stdlib_inlines.h
 #if __NDK_MAJOR__ <= 16
 #if __ANDROID_API__ < 21
-#include <support/xlocale/__strtonum_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
 #elif __ANDROID_API__ < 26
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
 inline _LIBCPP_INLINE_VISIBILITY float strtof_l(const char* __nptr, char** __endptr,
                                                 locale_t) {
   return ::strtof(__nptr, __endptr);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY double strtod_l(const char* __nptr,
                                                  char** __endptr, locale_t) {
   return ::strtod(__nptr, __endptr);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY long strtol_l(const char* __nptr, char** __endptr,
                                                int __base, locale_t) {
   return ::strtol(__nptr, __endptr, __base);
 }
 
 #if defined(__cplusplus)
 }
 #endif
 
 #endif // __ANDROID_API__ < 26
 
 #endif // __NDK_MAJOR__ <= 16
 #endif // defined(__ANDROID__)
 
 #endif // defined(__BIONIC__)
 #endif // _LIBCPP_SUPPORT_ANDROID_LOCALE_BIONIC_H

libcxx/include/__support/fuchsia/xlocale.h

 // -*- C++ -*-
-//===------------------- support/fuchsia/xlocale.h ------------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_FUCHSIA_XLOCALE_H
 #define _LIBCPP_SUPPORT_FUCHSIA_XLOCALE_H
 
 #if defined(__Fuchsia__)
 
 #include <cstdlib>
 #include <cwchar>
-#include <support/xlocale/__posix_l_fallback.h>
-#include <support/xlocale/__strtonum_fallback.h>
+#include <__support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
 
 #endif // defined(__Fuchsia__)
 
 #endif // _LIBCPP_SUPPORT_FUCHSIA_XLOCALE_H

libcxx/include/__support/ibm/limits.h

 // -*- C++ -*-
-//===--------------------- support/ibm/limits.h ---------------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_IBM_LIMITS_H
 #define _LIBCPP_SUPPORT_IBM_LIMITS_H
 
 #if !defined(_AIX) // Linux
 #include <math.h> // for HUGE_VAL, HUGE_VALF, HUGE_VALL, and NAN
 
 static const unsigned int _QNAN_F = 0x7fc00000;
 #define NANF (*((float *)(&_QNAN_F)))
 static const unsigned int _QNAN_LDBL128[4] = {0x7ff80000, 0x0, 0x0, 0x0};
 #define NANL (*((long double *)(&_QNAN_LDBL128)))
 static const unsigned int _SNAN_F= 0x7f855555;
 #define NANSF (*((float *)(&_SNAN_F)))
 static const unsigned int _SNAN_D[2] = {0x7ff55555, 0x55555555};
 #define NANS (*((double *)(&_SNAN_D)))
 static const unsigned int _SNAN_LDBL128[4] = {0x7ff55555, 0x55555555, 0x0, 0x0};
 #define NANSL (*((long double *)(&_SNAN_LDBL128)))
 
 #define __builtin_huge_val()     HUGE_VAL
 #define __builtin_huge_valf()    HUGE_VALF
 #define __builtin_huge_vall()    HUGE_VALL
 #define __builtin_nan(__dummy)   NAN
 #define __builtin_nanf(__dummy)  NANF
 #define __builtin_nanl(__dummy)  NANL
 #define __builtin_nans(__dummy)  NANS
 #define __builtin_nansf(__dummy) NANSF
 #define __builtin_nansl(__dummy) NANSL
 
 #else
 
 #include <math.h>
 #include <float.h> // limit constants
 
 #define __builtin_huge_val()     HUGE_VAL  //0x7ff0000000000000
 #define __builtin_huge_valf()    HUGE_VALF //0x7f800000
 #define __builtin_huge_vall()    HUGE_VALL //0x7ff0000000000000
 #define __builtin_nan(__dummy)   nan(__dummy) //0x7ff8000000000000
 #define __builtin_nanf(__dummy)  nanf(__dummy) // 0x7ff80000
 #define __builtin_nanl(__dummy)  nanl(__dummy) //0x7ff8000000000000
 #define __builtin_nans(__dummy)  DBL_SNAN //0x7ff5555555555555
 #define __builtin_nansf(__dummy) FLT_SNAN //0x7f855555
 #define __builtin_nansl(__dummy) DBL_SNAN //0x7ff5555555555555
 
 #define __FLT_MANT_DIG__   FLT_MANT_DIG
 #define __FLT_DIG__        FLT_DIG
 #define __FLT_RADIX__      FLT_RADIX
 #define __FLT_MIN_EXP__    FLT_MIN_EXP
 #define __FLT_MIN_10_EXP__ FLT_MIN_10_EXP
 #define __FLT_MAX_EXP__    FLT_MAX_EXP
 #define __FLT_MAX_10_EXP__ FLT_MAX_10_EXP
 #define __FLT_MIN__        FLT_MIN
 #define __FLT_MAX__        FLT_MAX
 #define __FLT_EPSILON__    FLT_EPSILON
 // predefined by XLC on LoP
 #define __FLT_DENORM_MIN__ 1.40129846e-45F
 
 #define __DBL_MANT_DIG__   DBL_MANT_DIG
 #define __DBL_DIG__        DBL_DIG
 #define __DBL_MIN_EXP__    DBL_MIN_EXP
 #define __DBL_MIN_10_EXP__ DBL_MIN_10_EXP
 #define __DBL_MAX_EXP__    DBL_MAX_EXP
 #define __DBL_MAX_10_EXP__ DBL_MAX_10_EXP
 #define __DBL_MIN__        DBL_MIN
 #define __DBL_MAX__        DBL_MAX
 #define __DBL_EPSILON__    DBL_EPSILON
 // predefined by XLC on LoP
 #define __DBL_DENORM_MIN__ 4.9406564584124654e-324
 
 #define __LDBL_MANT_DIG__   LDBL_MANT_DIG
 #define __LDBL_DIG__        LDBL_DIG
 #define __LDBL_MIN_EXP__    LDBL_MIN_EXP
 #define __LDBL_MIN_10_EXP__ LDBL_MIN_10_EXP
 #define __LDBL_MAX_EXP__    LDBL_MAX_EXP
 #define __LDBL_MAX_10_EXP__ LDBL_MAX_10_EXP
 #define __LDBL_MIN__        LDBL_MIN
 #define __LDBL_MAX__        LDBL_MAX
 #define __LDBL_EPSILON__    LDBL_EPSILON
 // predefined by XLC on LoP
 #if __LONGDOUBLE128
 #define __LDBL_DENORM_MIN__ 4.94065645841246544176568792868221e-324L
 #else
 #define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
 #endif
 
 // predefined by XLC on LoP
 #define __CHAR_BIT__    8
 
 #endif // _AIX
 
 #endif // _LIBCPP_SUPPORT_IBM_LIMITS_H

libcxx/include/__support/ibm/locale_mgmt_aix.h

 // -*- C++ -*-
-//===------------------- support/ibm/locale_mgmt_aix.h --------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_IBM_LOCALE_MGMT_AIX_H
 #define _LIBCPP_SUPPORT_IBM_LOCALE_MGMT_AIX_H
 
 #if defined(_AIX)
 #include "cstdlib"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 #if !defined(_AIX71)
 // AIX 7.1 and higher has these definitions.  Definitions and stubs
 // are provied here as a temporary workaround on AIX 6.1.
 
 #define LC_COLLATE_MASK         1
 #define LC_CTYPE_MASK           2
 #define LC_MESSAGES_MASK        4
 #define LC_MONETARY_MASK        8
 #define LC_NUMERIC_MASK         16
 #define LC_TIME_MASK            32
 #define LC_ALL_MASK             (LC_COLLATE_MASK | LC_CTYPE_MASK | \
                                  LC_MESSAGES_MASK | LC_MONETARY_MASK |\
                                  LC_NUMERIC_MASK | LC_TIME_MASK)
 
 typedef void* locale_t;
 
 // The following are stubs.  They are not supported on AIX 6.1.
 static inline
 locale_t newlocale(int category_mask, const char *locale, locale_t base)
 {
   _LC_locale_t *newloc, *loc;
   if ((loc = (_LC_locale_t *)__xopen_locale(locale)) == NULL)
   {
     errno = EINVAL;
     return (locale_t)0;
   }
   if ((newloc = (_LC_locale_t *)calloc(1, sizeof(_LC_locale_t))) == NULL)
   {
     errno = ENOMEM;
     return (locale_t)0;
   }
   if (!base)
     base = (_LC_locale_t *)__xopen_locale("C");
   memcpy(newloc, base, sizeof (_LC_locale_t));
   if (category_mask & LC_COLLATE_MASK)
     newloc->lc_collate = loc->lc_collate;
   if (category_mask & LC_CTYPE_MASK)
     newloc->lc_ctype = loc->lc_ctype;
   //if (category_mask & LC_MESSAGES_MASK)
   //  newloc->lc_messages = loc->lc_messages;
   if (category_mask & LC_MONETARY_MASK)
     newloc->lc_monetary = loc->lc_monetary;
   if (category_mask & LC_TIME_MASK)
     newloc->lc_time = loc->lc_time;
   if (category_mask & LC_NUMERIC_MASK)
     newloc->lc_numeric = loc->lc_numeric;
   return (locale_t)newloc;
 }
 static inline
 void freelocale(locale_t locobj)
 {
   free(locobj);
 }
 static inline
 locale_t uselocale(locale_t newloc)
 {
   return (locale_t)0;
 }
 #endif // !defined(_AIX71)
 
 #ifdef __cplusplus
 }
 #endif
 #endif // defined(_AIX)
 #endif // _LIBCPP_SUPPORT_IBM_LOCALE_MGMT_AIX_H

libcxx/include/__support/ibm/nanosleep.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
 #define _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
 
 #include <unistd.h>
 
 inline int nanosleep(const struct timespec* req, struct timespec* rem)
 {
    // The nanosleep() function is not available on z/OS. Therefore, we will call
    // sleep() to sleep for whole seconds and usleep() to sleep for any remaining
    // fraction of a second. Any remaining nanoseconds will round up to the next
    // microsecond.
 
    useconds_t __micro_sec = (rem->tv_nsec + 999) / 1000;
    if (__micro_sec > 999999)
    {
      ++rem->tv_sec;
      __micro_sec -= 1000000;
    }
    while (rem->tv_sec)
       rem->tv_sec = sleep(rem->tv_sec);
    if (__micro_sec) {
      rem->tv_nsec = __micro_sec * 1000;
      return usleep(__micro_sec);
    }
    rem->tv_nsec = 0;
    return 0;
 }
 
 #endif // _LIBCPP_SUPPORT_IBM_NANOSLEEP_H

libcxx/include/__support/ibm/support.h

 // -*- C++ -*-
-//===----------------------- support/ibm/support.h ----------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_IBM_SUPPORT_H
 #define _LIBCPP_SUPPORT_IBM_SUPPORT_H
 
 extern "builtin" int __popcnt4(unsigned int);
 extern "builtin" int __popcnt8(unsigned long long);
 extern "builtin" unsigned int __cnttz4(unsigned int);
 extern "builtin" unsigned int __cnttz8(unsigned long long);
 extern "builtin" unsigned int __cntlz4(unsigned int);
 extern "builtin" unsigned int __cntlz8(unsigned long long);
 
 // Builtin functions for counting population
 #define __builtin_popcount(x) __popcnt4(x)
 #define __builtin_popcountll(x) __popcnt8(x)
 #if defined(__64BIT__)
 #define __builtin_popcountl(x) __builtin_popcountll(x)
 #else
 #define __builtin_popcountl(x) __builtin_popcount(x)

libcxx/include/__support/ibm/xlocale.h

 // -*- C++ -*-
-//===--------------------- support/ibm/xlocale.h -------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_IBM_XLOCALE_H
 #define _LIBCPP_SUPPORT_IBM_XLOCALE_H
-#include <support/ibm/locale_mgmt_aix.h>
+
+#include <__support/ibm/locale_mgmt_aix.h>
 
 #include "cstdlib"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 #if defined(_AIX)
 #if !defined(_AIX71)
 // AIX 7.1 and higher has these definitions.  Definitions and stubs
 // are provied here as a temporary workaround on AIX 6.1.
 static inline
 int isalnum_l(int c, locale_t locale)
 {
   return __xisalnum(locale, c);
 }
 static inline
 int isalpha_l(int c, locale_t locale)
 {
   return __xisalpha(locale, c);
 }
 static inline
 int isblank_l(int c, locale_t locale)
 {
   return __xisblank(locale, c);
 }
 static inline
 int iscntrl_l(int c, locale_t locale)
 {
   return __xiscntrl(locale, c);
 }
 static inline
 int isdigit_l(int c, locale_t locale)
 {
   return __xisdigit(locale, c);
 }
 static inline
 int isgraph_l(int c, locale_t locale)
 {
   return __xisgraph(locale, c);
 }
 static inline
 int islower_l(int c, locale_t locale)
 {
   return __xislower(locale, c);
 }
 static inline
 int isprint_l(int c, locale_t locale)
 {
   return __xisprint(locale, c);
 }
 
 static inline
 int ispunct_l(int c, locale_t locale)
 {
   return __xispunct(locale, c);
 }
 static inline
 int isspace_l(int c, locale_t locale)
 {
   return __xisspace(locale, c);
 }
 static inline
 int isupper_l(int c, locale_t locale)
 {
   return __xisupper(locale, c);
 }
 
 static inline
 int isxdigit_l(int c, locale_t locale)
 {
   return __xisxdigit(locale, c);
 }
 
 static inline
 int iswalnum_l(wchar_t wc, locale_t locale)
 {
   return __xiswalnum(locale, wc);
 }
 
 static inline
 int iswalpha_l(wchar_t wc, locale_t locale)
 {
   return __xiswalpha(locale, wc);
 }
 
 static inline
 int iswblank_l(wchar_t wc, locale_t locale)
 {
   return __xiswblank(locale, wc);
 }
 
 static inline
 int iswcntrl_l(wchar_t wc, locale_t locale)
 {
   return __xiswcntrl(locale, wc);
 }
 
 static inline
 int iswdigit_l(wchar_t wc, locale_t locale)
 {
   return __xiswdigit(locale, wc);
 }
 
 static inline
 int iswgraph_l(wchar_t wc, locale_t locale)
 {
   return __xiswgraph(locale, wc);
 }
 
 static inline
 int iswlower_l(wchar_t wc, locale_t locale)
 {
   return __xiswlower(locale, wc);
 }
 
 static inline
 int iswprint_l(wchar_t wc, locale_t locale)
 {
   return __xiswprint(locale, wc);
 }
 
 static inline
 int iswpunct_l(wchar_t wc, locale_t locale)
 {
   return __xiswpunct(locale, wc);
 }
 
 static inline
 int iswspace_l(wchar_t wc, locale_t locale)
 {
   return __xiswspace(locale, wc);
 }
 
 static inline
 int iswupper_l(wchar_t wc, locale_t locale)
 {
   return __xiswupper(locale, wc);
 }
 
 static inline
 int iswxdigit_l(wchar_t wc, locale_t locale)
 {
   return __xiswxdigit(locale, wc);
 }
 
 static inline
 int iswctype_l(wint_t wc, wctype_t desc, locale_t locale)
 {
   return __xiswctype(locale, wc, desc);
 }
 
 static inline
 int toupper_l(int c, locale_t locale)
 {
   return __xtoupper(locale, c);
 }
 static inline
 int tolower_l(int c, locale_t locale)
 {
   return __xtolower(locale, c);
 }
 static inline
 wint_t towupper_l(wint_t wc, locale_t locale)
 {
   return __xtowupper(locale, wc);
 }
 static inline
 wint_t towlower_l(wint_t wc, locale_t locale)
 {
   return __xtowlower(locale, wc);
 }
 
 static inline
 int strcoll_l(const char *__s1, const char *__s2, locale_t locale)
 {
   return __xstrcoll(locale, __s1, __s2);
 }
 static inline
 int wcscoll_l(const wchar_t *__s1, const wchar_t *__s2, locale_t locale)
 {
   return __xwcscoll(locale, __s1, __s2);
 }
 static inline
 size_t strxfrm_l(char *__s1, const char *__s2, size_t __n, locale_t locale)
 {
   return __xstrxfrm(locale, __s1, __s2, __n);
 }
 
 static inline
 size_t wcsxfrm_l(wchar_t *__ws1, const wchar_t *__ws2, size_t __n,
     locale_t locale)
 {
   return __xwcsxfrm(locale, __ws1, __ws2, __n);
 }
 #endif // !defined(_AIX71)
 
 // strftime_l() is defined by POSIX. However, AIX 7.1 and z/OS do not have it
 // implemented yet. z/OS retrieves it from the POSIX fallbacks.
 static inline
 size_t strftime_l(char *__s, size_t __size, const char *__fmt,
                   const struct tm *__tm, locale_t locale) {
   return __xstrftime(locale, __s, __size, __fmt, __tm);
 }
 
 #elif defined(__MVS__)
 #include <wctype.h>
 // POSIX routines
-#include <support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__posix_l_fallback.h>
 #endif // defined(__MVS__)
 
 // The following are not POSIX routines.  These are quick-and-dirty hacks
 // to make things pretend to work
 static inline
 long long strtoll_l(const char *__nptr, char **__endptr,
     int __base, locale_t locale) {
   return strtoll(__nptr, __endptr, __base);
 }
 static inline
 long strtol_l(const char *__nptr, char **__endptr,
     int __base, locale_t locale) {
   return strtol(__nptr, __endptr, __base);
 }
 static inline
 long double strtold_l(const char *__nptr, char **__endptr,
     locale_t locale) {
   return strtold(__nptr, __endptr);
 }
 static inline
 unsigned long long strtoull_l(const char *__nptr, char **__endptr,
     int __base, locale_t locale) {
   return strtoull(__nptr, __endptr, __base);
 }
 static inline
 unsigned long strtoul_l(const char *__nptr, char **__endptr,
     int __base, locale_t locale) {
   return strtoul(__nptr, __endptr, __base);
 }
 
 static inline
 int vasprintf(char **strp, const char *fmt, va_list ap)
 {
   const size_t buff_size = 256;
   int str_size;
   if ((*strp = (char *)malloc(buff_size)) == NULL)
   {
     return -1;
   }
   if ((str_size = vsnprintf(*strp, buff_size, fmt,  ap)) >= buff_size)
   {
     if ((*strp = (char *)realloc(*strp, str_size + 1)) == NULL)
     {
       return -1;
     }
     str_size = vsnprintf(*strp, str_size + 1, fmt,  ap);
   }
   return str_size;
 }
 
 #ifdef __cplusplus
 }
 #endif
 #endif // _LIBCPP_SUPPORT_IBM_XLOCALE_H

libcxx/include/__support/musl/xlocale.h

 // -*- C++ -*-
-//===------------------- support/musl/xlocale.h ------------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 // This adds support for the extended locale functions that are currently
 // missing from the Musl C library.
 //
 // This only works when the specified locale is "C" or "POSIX", but that's
 // about as good as we can do without implementing full xlocale support
 // in Musl.
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_MUSL_XLOCALE_H
 #define _LIBCPP_SUPPORT_MUSL_XLOCALE_H
 
 #include <cstdlib>
 #include <cwchar>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 static inline long long strtoll_l(const char *nptr, char **endptr, int base,
                                   locale_t) {
   return strtoll(nptr, endptr, base);
 }
 
 static inline unsigned long long strtoull_l(const char *nptr, char **endptr,
                                             int base, locale_t) {
   return strtoull(nptr, endptr, base);
 }
 
 static inline long long wcstoll_l(const wchar_t *nptr, wchar_t **endptr,
                                   int base, locale_t) {
   return wcstoll(nptr, endptr, base);
 }
 
 static inline unsigned long long wcstoull_l(const wchar_t *nptr,
                                             wchar_t **endptr, int base,
                                             locale_t) {
   return wcstoull(nptr, endptr, base);
 }
 
 static inline long double wcstold_l(const wchar_t *nptr, wchar_t **endptr,
                                     locale_t) {
   return wcstold(nptr, endptr);
 }
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // _LIBCPP_SUPPORT_MUSL_XLOCALE_H

libcxx/include/__support/newlib/xlocale.h

 #define _LIBCPP_SUPPORT_NEWLIB_XLOCALE_H
 
 #if defined(_NEWLIB_VERSION)
 
 #include <cstdlib>
 #include <clocale>
 #include <cwctype>
 #include <ctype.h>
 #if !defined(__NEWLIB__) || __NEWLIB__ < 2 || \
     __NEWLIB__ == 2 && __NEWLIB_MINOR__ < 5
-#include <support/xlocale/__nop_locale_mgmt.h>
-#include <support/xlocale/__posix_l_fallback.h>
-#include <support/xlocale/__strtonum_fallback.h>
+#include <__support/xlocale/__nop_locale_mgmt.h>
+#include <__support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
 #endif
 
 #endif // _NEWLIB_VERSION
 
 #endif

libcxx/include/__support/nuttx/xlocale.h

 // -*- C++ -*-
-//===-------------------- support/nuttx/xlocale.h -------------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_NUTTX_XLOCALE_H
 #define _LIBCPP_SUPPORT_NUTTX_XLOCALE_H
 
 #if defined(__NuttX__)
-#include <support/xlocale/__posix_l_fallback.h>
-#include <support/xlocale/__strtonum_fallback.h>
+#include <__support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
 #endif // __NuttX__
 
 #endif

libcxx/include/__support/openbsd/xlocale.h

 // -*- C++ -*-
-//===-------------------- support/openbsd/xlocale.h -----------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_OPENBSD_XLOCALE_H
 #define _LIBCPP_SUPPORT_OPENBSD_XLOCALE_H
 
 #include <cstdlib>
 #include <clocale>
 #include <cwctype>
 #include <ctype.h>
-#include <support/xlocale/__strtonum_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
 
 #endif

libcxx/include/__support/solaris/floatingpoint.h

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #define atof sun_atof
 #define strtod sun_strtod
 #include_next "floatingpoint.h"
 #undef atof
 #undef strtod

libcxx/include/__support/solaris/wchar.h

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #define iswalpha sun_iswalpha
 #define iswupper sun_iswupper
 #define iswlower sun_iswlower
 #define iswdigit sun_iswdigit
 #define iswxdigit sun_iswxdigit
 #define iswalnum sun_iswalnum
 #define iswspace sun_iswspace
 #define iswpunct sun_iswpunct
 #define iswprint sun_iswprint
 #define iswgraph sun_iswgraph
 #define iswcntrl sun_iswcntrl
 #define iswctype sun_iswctype
 #define towlower sun_towlower
 #define towupper sun_towupper
 #define wcswcs sun_wcswcs
 #define wcswidth sun_wcswidth
 #define wcwidth sun_wcwidth
 #define wctype sun_wctype
 #define _WCHAR_T 1
 #include_next "wchar.h"
 #undef iswalpha
 #undef iswupper
 #undef iswlower
 #undef iswdigit
 #undef iswxdigit
 #undef iswalnum
 #undef iswspace
 #undef iswpunct
 #undef iswprint
 #undef iswgraph
 #undef iswcntrl
 #undef iswctype
 #undef towlower
 #undef towupper
 #undef wcswcs
 #undef wcswidth
 #undef wcwidth
 #undef wctype

libcxx/include/__support/solaris/xlocale.h

 #ifndef __XLOCALE_H_INCLUDED
 #define __XLOCALE_H_INCLUDED
 
 #include <stdlib.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
 int snprintf_l(char *__s, size_t __n, locale_t __l, const char *__format, ...);
 int asprintf_l(char **__s, locale_t __l, const char *__format, ...);
 
 int sscanf_l(const char *__s, locale_t __l, const char *__format, ...);
 
 int toupper_l(int __c, locale_t __l);
 int tolower_l(int __c, locale_t __l);
 
 struct lconv *localeconv(void);
 struct lconv *localeconv_l(locale_t __l);
 
 // FIXME: These are quick-and-dirty hacks to make things pretend to work
 static inline
 long long strtoll_l(const char *__nptr, char **__endptr,
     int __base, locale_t __loc) {
   return strtoll(__nptr, __endptr, __base);
 }
 static inline
 long strtol_l(const char *__nptr, char **__endptr,
     int __base, locale_t __loc) {
   return strtol(__nptr, __endptr, __base);
 }
 static inline
 unsigned long long strtoull_l(const char *__nptr, char **__endptr,
     int __base, locale_t __loc) {
   return strtoull(__nptr, __endptr, __base);
 }
 static inline
 unsigned long strtoul_l(const char *__nptr, char **__endptr,
     int __base, locale_t __loc) {
   return strtoul(__nptr, __endptr, __base);
 }
 static inline
 float strtof_l(const char *__nptr, char **__endptr,
     locale_t __loc) {
   return strtof(__nptr, __endptr);
 }
 static inline
 double strtod_l(const char *__nptr, char **__endptr,
     locale_t __loc) {
   return strtod(__nptr, __endptr);
 }
 static inline
 long double strtold_l(const char *__nptr, char **__endptr,
     locale_t __loc) {
   return strtold(__nptr, __endptr);
 }
 
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif

libcxx/include/__support/win32/limits_msvc_win32.h

 // -*- C++ -*-
-//===------------------ support/win32/limits_msvc_win32.h -----------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_WIN32_LIMITS_MSVC_WIN32_H
 #define _LIBCPP_SUPPORT_WIN32_LIMITS_MSVC_WIN32_H
 
 #if !defined(_LIBCPP_MSVCRT)
 #error "This header complements the Microsoft C Runtime library, and should not be included otherwise."
 #endif
 #if defined(__clang__)
 #error "This header should only be included when using Microsofts C1XX frontend"
 #endif
 
 #include <limits.h> // CHAR_BIT
 #include <float.h> // limit constants
 #include <math.h> // HUGE_VAL
 #include <ymath.h> // internal MSVC header providing the needed functionality
 
 #define __CHAR_BIT__       CHAR_BIT
 
 #define __FLT_MANT_DIG__   FLT_MANT_DIG
 #define __FLT_DIG__        FLT_DIG
 #define __FLT_RADIX__      FLT_RADIX
 #define __FLT_MIN_EXP__    FLT_MIN_EXP
 #define __FLT_MIN_10_EXP__ FLT_MIN_10_EXP
 #define __FLT_MAX_EXP__    FLT_MAX_EXP
 #define __FLT_MAX_10_EXP__ FLT_MAX_10_EXP
 #define __FLT_MIN__        FLT_MIN
 #define __FLT_MAX__        FLT_MAX
 #define __FLT_EPSILON__    FLT_EPSILON
 // predefined by MinGW GCC
 #define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F
 
 #define __DBL_MANT_DIG__   DBL_MANT_DIG
 #define __DBL_DIG__        DBL_DIG
 #define __DBL_RADIX__      DBL_RADIX
 #define __DBL_MIN_EXP__    DBL_MIN_EXP
 #define __DBL_MIN_10_EXP__ DBL_MIN_10_EXP
 #define __DBL_MAX_EXP__    DBL_MAX_EXP
 #define __DBL_MAX_10_EXP__ DBL_MAX_10_EXP
 #define __DBL_MIN__        DBL_MIN
 #define __DBL_MAX__        DBL_MAX
 #define __DBL_EPSILON__    DBL_EPSILON
 // predefined by MinGW GCC
 #define __DBL_DENORM_MIN__ double(4.94065645841246544177e-324L)
 
 #define __LDBL_MANT_DIG__   LDBL_MANT_DIG
 #define __LDBL_DIG__        LDBL_DIG
 #define __LDBL_RADIX__      LDBL_RADIX
 #define __LDBL_MIN_EXP__    LDBL_MIN_EXP
 #define __LDBL_MIN_10_EXP__ LDBL_MIN_10_EXP
 #define __LDBL_MAX_EXP__    LDBL_MAX_EXP
 #define __LDBL_MAX_10_EXP__ LDBL_MAX_10_EXP
 #define __LDBL_MIN__        LDBL_MIN
 #define __LDBL_MAX__        LDBL_MAX
 #define __LDBL_EPSILON__    LDBL_EPSILON
 // predefined by MinGW GCC
 #define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
 
 // __builtin replacements/workarounds
 #define __builtin_huge_vall()    _LInf._Long_double
 #define __builtin_nanl(__dummmy) _LNan._Long_double
 #define __builtin_nansl(__dummy) _LSnan._Long_double
 
 #endif // _LIBCPP_SUPPORT_WIN32_LIMITS_MSVC_WIN32_H

libcxx/include/__support/win32/locale_win32.h

 // -*- C++ -*-
-//===--------------------- support/win32/locale_win32.h -------------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H
 #define _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H
 
 #include <__config>
 #include <stdio.h>
 #include <xlocinfo.h> // _locale_t
 #include <__nullptr>
 
 #define LC_COLLATE_MASK _M_COLLATE
 #define LC_CTYPE_MASK _M_CTYPE
 #define LC_MONETARY_MASK _M_MONETARY
 #define LC_NUMERIC_MASK _M_NUMERIC
 #define LC_TIME_MASK _M_TIME
 #define LC_MESSAGES_MASK _M_MESSAGES
 #define LC_ALL_MASK (  LC_COLLATE_MASK \
                      | LC_CTYPE_MASK \
                      | LC_MESSAGES_MASK \
                      | LC_MONETARY_MASK \
                      | LC_NUMERIC_MASK \
                      | LC_TIME_MASK )
 
 class __lconv_storage {
 public:
     __lconv_storage(const lconv *__lc_input) {
         __lc = *__lc_input;
 
         __decimal_point = __lc_input->decimal_point;
         __thousands_sep = __lc_input->thousands_sep;
         __grouping = __lc_input->grouping;
         __int_curr_symbol = __lc_input->int_curr_symbol;
         __currency_symbol = __lc_input->currency_symbol;
         __mon_decimal_point = __lc_input->mon_decimal_point;
__lconv_storage(const lconv *__lc_input) {
         __lc.positive_sign = const_cast<char *>(__positive_sign.c_str());
         __lc.negative_sign = const_cast<char *>(__negative_sign.c_str());
     }
 
     lconv *__get() {
         return &__lc;
     }
 private:
     lconv __lc;
     std::string __decimal_point;
     std::string __thousands_sep;
     std::string __grouping;
     std::string __int_curr_symbol;
     std::string __currency_symbol;
     std::string __mon_decimal_point;
     std::string __mon_thousands_sep;
     std::string __mon_grouping;
     std::string __positive_sign;
     std::string __negative_sign;
 };
 
 class locale_t {
 public:
     locale_t()
         : __locale(nullptr), __locale_str(nullptr), __lc(nullptr) {}
     locale_t(std::nullptr_t)
         : __locale(nullptr), __locale_str(nullptr), __lc(nullptr) {}
     locale_t(_locale_t __xlocale, const char* __xlocale_str)
         : __locale(__xlocale), __locale_str(__xlocale_str), __lc(nullptr) {}
     locale_t(const locale_t &__l)
         : __locale(__l.__locale), __locale_str(__l.__locale_str), __lc(nullptr) {}
 
public:
     }
 
     lconv *__store_lconv(const lconv *__input_lc) {
         delete __lc;
         __lc = new __lconv_storage(__input_lc);
         return __lc->__get();
     }
 private:
     _locale_t __locale;
     const char* __locale_str;
     __lconv_storage *__lc = nullptr;
 };
 
 // Locale management functions
 #define freelocale _free_locale
 // FIXME: base currently unused. Needs manual work to construct the new locale
 locale_t newlocale( int mask, const char * locale, locale_t base );
 // uselocale can't be implemented on Windows because Windows allows partial modification
 // of thread-local locale and so _get_current_locale() returns a copy while uselocale does
 // not create any copies.
 // We can still implement raii even without uselocale though.
 
 
 lconv *localeconv_l( locale_t &loc );
 size_t mbrlen_l( const char *__restrict s, size_t n,
                  mbstate_t *__restrict ps, locale_t loc);
 size_t mbsrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
                     size_t len, mbstate_t *__restrict ps, locale_t loc );
 size_t wcrtomb_l( char *__restrict s, wchar_t wc, mbstate_t *__restrict ps,
                   locale_t loc);
 size_t mbrtowc_l( wchar_t *__restrict pwc, const char *__restrict s,

 #define strtod_l _strtod_l
 #if defined(_LIBCPP_MSVCRT)
 #define strtof_l _strtof_l
 #define strtold_l _strtold_l
 #else
 _LIBCPP_FUNC_VIS float strtof_l(const char*, char**, locale_t);
 _LIBCPP_FUNC_VIS long double strtold_l(const char*, char**, locale_t);
 #endif
 inline _LIBCPP_INLINE_VISIBILITY
 int
 islower_l(int c, _locale_t loc)
 {
  return _islower_l((int)c, loc);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY
 int
 isupper_l(int c, _locale_t loc)
 {
  return _isupper_l((int)c, loc);
 }
 
 #define isdigit_l _isdigit_l
 #define isxdigit_l _isxdigit_l

 #define iswlower_l _iswlower_l
 #define iswalpha_l _iswalpha_l
 #define iswdigit_l _iswdigit_l
 #define iswpunct_l _iswpunct_l
 #define iswxdigit_l _iswxdigit_l
 #define towupper_l _towupper_l
 #define towlower_l _towlower_l
 #if defined(__MINGW32__) && __MSVCRT_VERSION__ < 0x0800
 _LIBCPP_FUNC_VIS size_t strftime_l(char *ret, size_t n, const char *format,
                                    const struct tm *tm, locale_t loc);
 #else
 #define strftime_l _strftime_l
 #endif
 #define sscanf_l( __s, __l, __f, ...) _sscanf_l( __s, __f, __l, __VA_ARGS__ )
 #define sprintf_l( __s, __l, __f, ... ) _sprintf_l( __s, __f, __l, __VA_ARGS__ )
 #define vsprintf_l( __s, __l, __f, ... ) _vsprintf_l( __s, __f, __l, __VA_ARGS__ )
 #define vsnprintf_l( __s, __n, __l, __f, ... ) _vsnprintf_l( __s, __n, __f, __l, __VA_ARGS__ )
 _LIBCPP_FUNC_VIS int snprintf_l(char *ret, size_t n, locale_t loc, const char *format, ...);
 _LIBCPP_FUNC_VIS int asprintf_l( char **ret, locale_t loc, const char *format, ... );
 _LIBCPP_FUNC_VIS int vasprintf_l( char **ret, locale_t loc, const char *format, va_list ap );
 
 // not-so-pressing FIXME: use locale to determine blank characters
 inline int isblank_l( int c, locale_t /*loc*/ )
 {
     return ( c == ' ' || c == '\t' );
 }
 inline int iswblank_l( wint_t c, locale_t /*loc*/ )
 {
     return ( c == L' ' || c == L'\t' );
 }
 
 #endif // _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H

libcxx/include/__support/xlocale/__nop_locale_mgmt.h

 // -*- C++ -*-
-//===------------  support/xlocale/__nop_locale_mgmt.h -----------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H
 #define _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 // Patch over lack of extended locale support
 typedef void *locale_t;
 static inline locale_t duplocale(locale_t) {
   return NULL;
 }
 
 static inline void freelocale(locale_t) {
 }
 
 static inline locale_t newlocale(int, const char *, locale_t) {
   return NULL;
 }
 
 static inline locale_t uselocale(locale_t) {
   return NULL;
 }
 
 #define LC_COLLATE_MASK  (1 << LC_COLLATE)
 #define LC_CTYPE_MASK    (1 << LC_CTYPE)
 #define LC_MESSAGES_MASK (1 << LC_MESSAGES)
 #define LC_MONETARY_MASK (1 << LC_MONETARY)
 #define LC_NUMERIC_MASK  (1 << LC_NUMERIC)
 #define LC_TIME_MASK     (1 << LC_TIME)
 #define LC_ALL_MASK (LC_COLLATE_MASK|\
                      LC_CTYPE_MASK|\
                      LC_MONETARY_MASK|\
                      LC_NUMERIC_MASK|\
                      LC_TIME_MASK|\
                      LC_MESSAGES_MASK)
 
 #ifdef __cplusplus
 } // extern "C"
 #endif
 
 #endif // _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H

libcxx/include/__support/xlocale/__posix_l_fallback.h

 // -*- C++ -*-
-//===--------------- support/xlocale/__posix_l_fallback.h -----------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 // These are reimplementations of some extended locale functions ( *_l ) that
 // are normally part of POSIX.  This shared implementation provides parts of the
 // extended locale support for libc's that normally don't have any (like
 // Android's bionic and Newlib).
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H
 #define _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 inline _LIBCPP_INLINE_VISIBILITY int isalnum_l(int c, locale_t) {
   return ::isalnum(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int isalpha_l(int c, locale_t) {
   return ::isalpha(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int isblank_l(int c, locale_t) {
   return ::isblank(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int iscntrl_l(int c, locale_t) {
   return ::iscntrl(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int isdigit_l(int c, locale_t) {
   return ::isdigit(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int isgraph_l(int c, locale_t) {
   return ::isgraph(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int islower_l(int c, locale_t) {
   return ::islower(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int isprint_l(int c, locale_t) {
   return ::isprint(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int ispunct_l(int c, locale_t) {

 inline _LIBCPP_INLINE_VISIBILITY wint_t towupper_l(wint_t c, locale_t) {
   return ::towupper(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY wint_t towlower_l(wint_t c, locale_t) {
   return ::towlower(c);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int strcoll_l(const char *s1, const char *s2,
                                                locale_t) {
   return ::strcoll(s1, s2);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY size_t strxfrm_l(char *dest, const char *src,
                                                   size_t n, locale_t) {
   return ::strxfrm(dest, src, n);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY size_t strftime_l(char *s, size_t max,
                                                    const char *format,
                                                    const struct tm *tm, locale_t) {
   return ::strftime(s, max, format, tm);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY int wcscoll_l(const wchar_t *ws1,
                                                const wchar_t *ws2, locale_t) {
   return ::wcscoll(ws1, ws2);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY size_t wcsxfrm_l(wchar_t *dest, const wchar_t *src,
                                                   size_t n, locale_t) {
   return ::wcsxfrm(dest, src, n);
 }
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H

libcxx/include/__support/xlocale/__strtonum_fallback.h

 // -*- C++ -*-
-//===-------------- support/xlocale/__strtonum_fallback.h -----------------===//
+//===-----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 // These are reimplementations of some extended locale functions ( *_l ) that
 // aren't part of POSIX.  They are widely available though (GLIBC, BSD, maybe
 // others).  The unifying aspect in this case is that all of these functions
 // convert strings to some numeric type.
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H
 #define _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 inline _LIBCPP_INLINE_VISIBILITY float strtof_l(const char *nptr,
                                                 char **endptr, locale_t) {
   return ::strtof(nptr, endptr);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY double strtod_l(const char *nptr,
                                                  char **endptr, locale_t) {
   return ::strtod(nptr, endptr);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY long double strtold_l(const char *nptr,
                                                        char **endptr, locale_t) {
   return ::strtold(nptr, endptr);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY long long
 strtoll_l(const char *nptr, char **endptr, int base, locale_t) {
   return ::strtoll(nptr, endptr, base);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY unsigned long long
 strtoull_l(const char *nptr, char **endptr, int base, locale_t) {
   return ::strtoull(nptr, endptr, base);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY long long
 wcstoll_l(const wchar_t *nptr, wchar_t **endptr, int base, locale_t) {
   return ::wcstoll(nptr, endptr, base);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY unsigned long long
 wcstoull_l(const wchar_t *nptr, wchar_t **endptr, int base, locale_t) {
   return ::wcstoull(nptr, endptr, base);
 }
 
 inline _LIBCPP_INLINE_VISIBILITY long double wcstold_l(const wchar_t *nptr,
                                                        wchar_t **endptr, locale_t) {
   return ::wcstold(nptr, endptr);
 }
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H

libcxx/include/__threading_support

 
 #include <__config>
 #include <__availability>
 #include <chrono>
 #include <iosfwd>
 #include <errno.h>
 
 #ifdef __MVS__
-# include <support/ibm/nanosleep.h>
+# include <__support/ibm/nanosleep.h>
 #endif
 
 #ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
 #pragma GCC system_header
 #endif
 
 #if defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
 # include <__external_threading>

libcxx/include/bit

 #include <__config>
 #include <__bits>
 #include <limits>
 #include <type_traits>
 #include <version>
 #include <__debug>
 
 #if defined(__IBMCPP__)
-#include "support/ibm/support.h"
+#include "__support/ibm/support.h"
 #endif
 #if defined(_LIBCPP_COMPILER_MSVC)
 #include <intrin.h>
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif

libcxx/include/limits

 
 }  // std
 
 */
 #include <__config>
 #include <type_traits>
 
 #if defined(_LIBCPP_COMPILER_MSVC)
-#include "support/win32/limits_msvc_win32.h"
+#include "__support/win32/limits_msvc_win32.h"
 #endif // _LIBCPP_MSVCRT
 
 #if defined(__IBMCPP__)
-#include "support/ibm/limits.h"
+#include "__support/ibm/limits.h"
 #endif // __IBMCPP__
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>

libcxx/src/CMakeLists.txt

list(APPEND LIBCXX_SOURCES
       )
   endif()
 endif()
 
 # Add all the headers to the project for IDEs.
 if (LIBCXX_CONFIGURE_IDE)
   file(GLOB_RECURSE LIBCXX_HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/../include/*)
   if(WIN32)
-    file( GLOB LIBCXX_WIN32_HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/../include/support/win32/*.h)
+    file( GLOB LIBCXX_WIN32_HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/../include/__support/win32/*.h)
     list(APPEND LIBCXX_HEADERS ${LIBCXX_WIN32_HEADERS})
   endif()
   # Force them all into the headers dir on MSVC, otherwise they end up at
   # project scope because they don't have extensions.
   if (MSVC_IDE)
     source_group("Header Files" FILES ${LIBCXX_HEADERS})
   endif()
 endif()

libcxx/src/locale.cpp

 #  include "type_traits"
 #endif
 #include "clocale"
 #include "cstring"
 #if defined(_LIBCPP_MSVCRT)
 #define _CTYPE_DISABLE_MACROS
 #endif
 #include "cwctype"
 #include "__sso_allocator"
 #if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
-#include "support/win32/locale_win32.h"
+#include "__support/win32/locale_win32.h"
 #elif !defined(__BIONIC__) && !defined(__NuttX__)
 #include <langinfo.h>
 #endif
 #include <stdlib.h>
 #include <stdio.h>
 #include "include/atomic_support.h"
 #include "__undef_macros"
 

libcxx/src/support/solaris/xlocale.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifdef __sun__
 
-#include "support/solaris/xlocale.h"
+#include "__support/solaris/xlocale.h"
 #include <stdarg.h>
 #include <stdio.h>
 #include <sys/localedef.h>
 
 extern "C" {
 
 int isxdigit_l(int __c, locale_t __l) {
     return isxdigit(__c);

libcxx/src/support/win32/locale_win32.cpp

 // -*- C++ -*-
-//===-------------------- support/win32/locale_win32.cpp ------------------===//
+//===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include <locale>
 #include <cstdarg> // va_start, va_end
 #include <memory>
 #include <type_traits>
 
 int __libcpp_vasprintf(char **sptr, const char *__restrict fmt, va_list ap);
 
 using std::__libcpp_locale_guard;
 
 // FIXME: base currently unused. Needs manual work to construct the new locale
 locale_t newlocale( int mask, const char * locale, locale_t /*base*/ )
 {
     return {_create_locale( LC_ALL, locale ), locale};
 }
 
 decltype(MB_CUR_MAX) MB_CUR_MAX_L( locale_t __l )
 {
 #if defined(_LIBCPP_MSVCRT)
   return ___mb_cur_max_l_func(__l);
 #else
   __libcpp_locale_guard __current(__l);
   return MB_CUR_MAX;
 #endif
 }
 
 lconv *localeconv_l( locale_t &loc )
 {
     __libcpp_locale_guard __current(loc);
     lconv *lc = localeconv();
     if (!lc)
         return lc;
     return loc.__store_lconv(lc);
 }
 size_t mbrlen_l( const char *__restrict s, size_t n,
                  mbstate_t *__restrict ps, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return mbrlen( s, n, ps );
 }
 size_t mbsrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
                     size_t len, mbstate_t *__restrict ps, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return mbsrtowcs( dst, src, len, ps );
 }
 size_t wcrtomb_l( char *__restrict s, wchar_t wc, mbstate_t *__restrict ps,
                   locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return wcrtomb( s, wc, ps );
 }
 size_t mbrtowc_l( wchar_t *__restrict pwc, const char *__restrict s,
                   size_t n, mbstate_t *__restrict ps, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return mbrtowc( pwc, s, n, ps );
 }
 size_t mbsnrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
                      size_t nms, size_t len, mbstate_t *__restrict ps, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return mbsnrtowcs( dst, src, nms, len, ps );
 }
 size_t wcsnrtombs_l( char *__restrict dst, const wchar_t **__restrict src,
                      size_t nwc, size_t len, mbstate_t *__restrict ps, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return wcsnrtombs( dst, src, nwc, len, ps );
 }
 wint_t btowc_l( int c, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return btowc( c );
 }
 int wctob_l( wint_t c, locale_t loc )
 {
     __libcpp_locale_guard __current(loc);
     return wctob( c );
 }
 
 int snprintf_l(char *ret, size_t n, locale_t loc, const char *format, ...)
 {
     va_list ap;
     va_start( ap, format );
 #if defined(_LIBCPP_MSVCRT)
     // FIXME: Remove usage of internal CRT function and globals.
     int result = __stdio_common_vsprintf(
         _CRT_INTERNAL_LOCAL_PRINTF_OPTIONS | _CRT_INTERNAL_PRINTF_STANDARD_SNPRINTF_BEHAVIOR,
         ret, n, format, loc, ap);
 #else
     __libcpp_locale_guard __current(loc);
     int result = vsnprintf( ret, n, format, ap );
 #endif
     va_end(ap);
     return result;
 }
 
 int asprintf_l( char **ret, locale_t loc, const char *format, ... )
 {
     va_list ap;
     va_start( ap, format );
     int result = vasprintf_l( ret, loc, format, ap );
     va_end(ap);
     return result;
 }
 int vasprintf_l( char **ret, locale_t loc, const char *format, va_list ap )
 {
     __libcpp_locale_guard __current(loc);
     return __libcpp_vasprintf( ret, format, ap );
 }
 
 #if !defined(_LIBCPP_MSVCRT)
 float strtof_l(const char* nptr, char** endptr, locale_t loc) {
   __libcpp_locale_guard __current(loc);
   return strtof(nptr, endptr);
 }
 
 long double strtold_l(const char* nptr, char** endptr, locale_t loc) {
   __libcpp_locale_guard __current(loc);
   return strtold(nptr, endptr);
 }
 #endif
 
 #if defined(__MINGW32__) && __MSVCRT_VERSION__ < 0x0800
 size_t strftime_l(char *ret, size_t n, const char *format, const struct tm *tm,
                   locale_t loc) {
   __libcpp_locale_guard __current(loc);
   return strftime(ret, n, format, tm);
 }
 #endif

libcxx/src/support/win32/support.cpp

 // -*- C++ -*-
-//===----------------------- support/win32/support.h ----------------------===//
+//===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include <cstdarg> // va_start, va_end
 #include <cstddef> // size_t
 #include <cstdlib> // malloc
 #include <cstdio>  // vsprintf, vsnprintf
 #include <cstring> // strcpy, wcsncpy
 #include <cwchar>  // mbstate_t
 
 
 // Like sprintf, but when return value >= 0 it returns
 // a pointer to a malloc'd string in *sptr.
 // If return >= 0, use free to delete *sptr.
 int __libcpp_vasprintf( char **sptr, const char *__restrict format, va_list ap )
 {
     *sptr = NULL;
     // Query the count required.
     int count = _vsnprintf( NULL, 0, format, ap );
     if (count < 0)
         return count;
     size_t buffer_size = static_cast<size_t>(count) + 1;
     char* p = static_cast<char*>(malloc(buffer_size));
     if ( ! p )
         return -1;
     // If we haven't used exactly what was required, something is wrong.
     // Maybe bug in vsnprintf. Report the error and return.
     if (_vsnprintf(p, buffer_size, format, ap) != count) {
         free(p);
         return -1;
     }
     // All good. This is returning memory to the caller not freeing it.
     *sptr = p;
     return count;
 }
 
size_t wcsnrtombs( char *__restrict dst, const wchar_t **__restrict src,
                    size_t max_source_chars, size_t dst_size_bytes, mbstate_t *__restrict ps )
 {
     //const size_t invalid_sequence = static_cast<size_t>(-1);
 
     size_t source_converted = 0;
     size_t dest_converted = 0;
     size_t dest_remaining = dst_size_bytes;
     size_t char_size = 0;
     const errno_t no_error = ( errno_t) 0;
     errno_t result = ( errno_t ) 0;
     bool have_result = false;
     bool terminator_found = false;
 
     // If dst is null then dst_size_bytes should be ignored according to the
     // standard.  Setting dest_remaining to a large value has this effect.
     if (!dst)
         dest_remaining = static_cast<size_t>(-1);
 
     while ( source_converted != max_source_chars ) {
         if ( ! dest_remaining )
             break;
         wchar_t c = (*src)[source_converted];
         if ( dst )
             result = wcrtomb_s( &char_size, dst + dest_converted, dest_remaining, c, ps);
         else
             result = wcrtomb_s( &char_size, NULL, 0, c, ps);
         // If result is zero there is no error and char_size contains the
         // size of the multi-byte-sequence converted.
         // Otherwise result indicates an errno type error.
         if ( result == no_error ) {
             if ( c == L'\0' ) {
                 terminator_found = true;
                 break;
             }
             ++source_converted;
             if ( dst )
                 dest_remaining -= char_size;
             dest_converted += char_size;
             continue;
         }
         have_result = true;
         break;
     }
     if ( dst ) {
         if ( terminator_found )
             *src = NULL;
         else
             *src = *src + source_converted;
     }
     if ( have_result && result != no_error ) {
         errno = result;
         return static_cast<size_t>(-1);
     }
 
     return dest_converted;
 }

libcxx/src/support/win32/thread_win32.cpp

 // -*- C++ -*-
-//===-------------------- support/win32/thread_win32.cpp ------------------===//
+//===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include <__threading_support>
 #include <windows.h>
 #include <process.h>
 #include <fibersapi.h>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 static_assert(sizeof(__libcpp_mutex_t) == sizeof(SRWLOCK), "");
 static_assert(alignof(__libcpp_mutex_t) == alignof(SRWLOCK), "");

llvm/utils/gn/secondary/libcxx/include/BUILD.gn

sources = [
     "stdint.h",
     "stdio.h",
     "stdlib.h",
     "streambuf",
     "string",
     "string.h",
     "string_view",
     "strstream",
-    "support/android/locale_bionic.h",
-    "support/fuchsia/xlocale.h",
-    "support/ibm/limits.h",
-    "support/ibm/locale_mgmt_aix.h",
-    "support/ibm/nanosleep.h",
-    "support/ibm/support.h",
-    "support/ibm/xlocale.h",
-    "support/musl/xlocale.h",
-    "support/newlib/xlocale.h",
-    "support/nuttx/xlocale.h",
-    "support/openbsd/xlocale.h",
-    "support/solaris/floatingpoint.h",
-    "support/solaris/wchar.h",
-    "support/solaris/xlocale.h",
-    "support/win32/limits_msvc_win32.h",
-    "support/win32/locale_win32.h",
-    "support/xlocale/__nop_locale_mgmt.h",
-    "support/xlocale/__posix_l_fallback.h",
-    "support/xlocale/__strtonum_fallback.h",
+    "__support/android/locale_bionic.h",
+    "__support/fuchsia/xlocale.h",
+    "__support/ibm/limits.h",
+    "__support/ibm/locale_mgmt_aix.h",
+    "__support/ibm/nanosleep.h",
+    "__support/ibm/support.h",
+    "__support/ibm/xlocale.h",
+    "__support/musl/xlocale.h",
+    "__support/newlib/xlocale.h",
+    "__support/nuttx/xlocale.h",
+    "__support/openbsd/xlocale.h",
+    "__support/solaris/floatingpoint.h",
+    "__support/solaris/wchar.h",
+    "__support/solaris/xlocale.h",
+    "__support/win32/limits_msvc_win32.h",
+    "__support/win32/locale_win32.h",
+    "__support/xlocale/__nop_locale_mgmt.h",
+    "__support/xlocale/__posix_l_fallback.h",
+    "__support/xlocale/__strtonum_fallback.h",
     "system_error",
     "tgmath.h",
     "thread",
     "tuple",
     "type_traits",
     "typeindex",
     "typeinfo",
     "unordered_map",