[libc++] Add missing includes to xlocale helpers

[ldionne]

Summary

Also, make sure those are compatible with _LIBCPP_HAS_NO_WIDE_CHARACTERS.

libcxx/include/__support/xlocale/__nop_locale_mgmt.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_XLOCALE_NOP_LOCALE_MGMT_H
 #define _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H
 
+#include <__config>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 // Patch over lack of extended locale support
 typedef void *locale_t;
 
 inline _LIBCPP_HIDE_FROM_ABI locale_t

libcxx/include/__support/xlocale/__posix_l_fallback.h

 // 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
 
+#include <__config>
+#include <ctype.h>
+#include <time.h>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <wctype.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 inline _LIBCPP_HIDE_FROM_ABI int isalnum_l(int __c, locale_t) {
   return ::isalnum(__c);
 }
 

 inline _LIBCPP_HIDE_FROM_ABI int isupper_l(int __c, locale_t) {
   return ::isupper(__c);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI int isxdigit_l(int __c, locale_t) {
   return ::isxdigit(__c);
 }
 
+inline _LIBCPP_HIDE_FROM_ABI int toupper_l(int __c, locale_t) {
+  return ::toupper(__c);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI int tolower_l(int __c, locale_t) {
+  return ::tolower(__c);
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 inline _LIBCPP_HIDE_FROM_ABI int iswalnum_l(wint_t __c, locale_t) {
   return ::iswalnum(__c);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI int iswalpha_l(wint_t __c, locale_t) {
   return ::iswalpha(__c);
 }
 

 inline _LIBCPP_HIDE_FROM_ABI int iswupper_l(wint_t __c, locale_t) {
   return ::iswupper(__c);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI int iswxdigit_l(wint_t __c, locale_t) {
   return ::iswxdigit(__c);
 }
 
-inline _LIBCPP_HIDE_FROM_ABI int toupper_l(int __c, locale_t) {
-  return ::toupper(__c);
-}
-
-inline _LIBCPP_HIDE_FROM_ABI int tolower_l(int __c, locale_t) {
-  return ::tolower(__c);
-}
-
 inline _LIBCPP_HIDE_FROM_ABI wint_t towupper_l(wint_t __c, locale_t) {
   return ::towupper(__c);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI wint_t towlower_l(wint_t __c, locale_t) {
   return ::towlower(__c);
 }
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 
 inline _LIBCPP_HIDE_FROM_ABI int
 strcoll_l(const char *__s1, const char *__s2, locale_t) {
   return ::strcoll(__s1, __s2);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI size_t
 strxfrm_l(char *__dest, const char *__src, size_t __n, locale_t) {
   return ::strxfrm(__dest, __src, __n);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI size_t
 strftime_l(char *__s, size_t __max, const char *__format, const struct tm *__tm,
            locale_t) {
   return ::strftime(__s, __max, __format, __tm);
 }
 
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 inline _LIBCPP_HIDE_FROM_ABI int
 wcscoll_l(const wchar_t *__ws1, const wchar_t *__ws2, locale_t) {
   return ::wcscoll(__ws1, __ws2);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI size_t
 wcsxfrm_l(wchar_t *__dest, const wchar_t *__src, size_t __n, locale_t) {
   return ::wcsxfrm(__dest, __src, __n);
 }
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H

libcxx/include/__support/xlocale/__strtonum_fallback.h

 // 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
 
+#include <__config>
+#include <stdlib.h>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <wchar.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 inline _LIBCPP_HIDE_FROM_ABI float
 strtof_l(const char *__nptr, char **__endptr, locale_t) {
   return ::strtof(__nptr, __endptr);
 }
strtoll_l(const char *__nptr, char **__endptr, int __base, locale_t) {
   return ::strtoll(__nptr, __endptr, __base);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI unsigned long long
 strtoull_l(const char *__nptr, char **__endptr, int __base, locale_t) {
   return ::strtoull(__nptr, __endptr, __base);
 }
 
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 inline _LIBCPP_HIDE_FROM_ABI long long
 wcstoll_l(const wchar_t *__nptr, wchar_t **__endptr, int __base, locale_t) {
   return ::wcstoll(__nptr, __endptr, __base);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI unsigned long long
 wcstoull_l(const wchar_t *__nptr, wchar_t **__endptr, int __base, locale_t) {
   return ::wcstoull(__nptr, __endptr, __base);
 }
 
 inline _LIBCPP_HIDE_FROM_ABI long double
 wcstold_l(const wchar_t *__nptr, wchar_t **__endptr, locale_t) {
   return ::wcstold(__nptr, __endptr);
 }
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H