Index: libcxx/trunk/include/__config
===================================================================
--- libcxx/trunk/include/__config
+++ libcxx/trunk/include/__config
@@ -804,7 +804,7 @@
 #define _LIBCPP_HAS_NO_STDOUT
 #endif
 
-#if defined(__ANDROID__) || defined(__CloudABI__)
+#if defined(__ANDROID__) || defined(__CloudABI__) || defined(_LIBCPP_HAS_MUSL_LIBC)
 #define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
 #endif
 
Index: libcxx/trunk/include/__locale
===================================================================
--- libcxx/trunk/include/__locale
+++ libcxx/trunk/include/__locale
@@ -361,7 +361,7 @@
     typedef __uint32_t mask;
 # elif defined(__FreeBSD__)
     typedef unsigned long mask;
-# elif defined(__EMSCRIPTEN__) || defined(__NetBSD__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+# elif defined(__EMSCRIPTEN__) || defined(__NetBSD__)
     typedef unsigned short mask;
 # endif
     static const mask space  = _CTYPE_S;
@@ -408,11 +408,7 @@
 # define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_ALPHA
 # define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_XDIGIT
 #else
-#if defined(_LIBCPP_HAS_MUSL_LIBC)
-    typedef unsigned short mask;
-#else
     typedef unsigned long mask;
-#endif
     static const mask space  = 1<<0;
     static const mask print  = 1<<1;
     static const mask cntrl  = 1<<2;
@@ -634,7 +630,7 @@
 #endif
     _LIBCPP_ALWAYS_INLINE const mask* table() const  _NOEXCEPT {return __tab_;}
     static const mask* classic_table()  _NOEXCEPT;
-#if defined(__GLIBC__) || defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#if defined(__GLIBC__) || defined(__EMSCRIPTEN__)
     static const int* __classic_upper_table() _NOEXCEPT;
     static const int* __classic_lower_table() _NOEXCEPT;
 #endif
Index: libcxx/trunk/src/locale.cpp
===================================================================
--- libcxx/trunk/src/locale.cpp
+++ libcxx/trunk/src/locale.cpp
@@ -813,7 +813,7 @@
 #ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
     return isascii(c) ? _DefaultRuneLocale.__mapupper[c] : c;
 #elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
-      defined(__NetBSD__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+      defined(__NetBSD__)
     return isascii(c) ? ctype<char>::__classic_upper_table()[c] : c;
 #else
     return (isascii(c) && iswlower_l(c, _LIBCPP_GET_C_LOCALE)) ? c-L'a'+L'A' : c;
@@ -827,7 +827,7 @@
 #ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
         *low = isascii(*low) ? _DefaultRuneLocale.__mapupper[*low] : *low;
 #elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
-      defined(__NetBSD__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+      defined(__NetBSD__)
         *low = isascii(*low) ? ctype<char>::__classic_upper_table()[*low]
                              : *low;
 #else
@@ -842,7 +842,7 @@
 #ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
     return isascii(c) ? _DefaultRuneLocale.__maplower[c] : c;
 #elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
-      defined(__NetBSD__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+      defined(__NetBSD__)
     return isascii(c) ? ctype<char>::__classic_lower_table()[c] : c;
 #else
     return (isascii(c) && isupper_l(c, _LIBCPP_GET_C_LOCALE)) ? c-L'A'+'a' : c;
@@ -856,7 +856,7 @@
 #ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
         *low = isascii(*low) ? _DefaultRuneLocale.__maplower[*low] : *low;
 #elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
-      defined(__NetBSD__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+      defined(__NetBSD__)
         *low = isascii(*low) ? ctype<char>::__classic_lower_table()[*low]
                              : *low;
 #else
@@ -925,7 +925,7 @@
       static_cast<char>(_DefaultRuneLocale.__mapupper[static_cast<ptrdiff_t>(c)]) : c;
 #elif defined(__NetBSD__)
     return static_cast<char>(__classic_upper_table()[static_cast<unsigned char>(c)]);
-#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
     return isascii(c) ?
       static_cast<char>(__classic_upper_table()[static_cast<unsigned char>(c)]) : c;
 #else
@@ -942,7 +942,7 @@
           static_cast<char>(_DefaultRuneLocale.__mapupper[static_cast<ptrdiff_t>(*low)]) : *low;
 #elif defined(__NetBSD__)
         *low = static_cast<char>(__classic_upper_table()[static_cast<unsigned char>(*low)]);
-#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
         *low = isascii(*low) ?
           static_cast<char>(__classic_upper_table()[static_cast<size_t>(*low)]) : *low;
 #else
@@ -959,7 +959,7 @@
       static_cast<char>(_DefaultRuneLocale.__maplower[static_cast<ptrdiff_t>(c)]) : c;
 #elif defined(__NetBSD__)
     return static_cast<char>(__classic_lower_table()[static_cast<unsigned char>(c)]);
-#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
     return isascii(c) ?
       static_cast<char>(__classic_lower_table()[static_cast<size_t>(c)]) : c;
 #else
@@ -975,7 +975,7 @@
         *low = isascii(*low) ? static_cast<char>(_DefaultRuneLocale.__maplower[static_cast<ptrdiff_t>(*low)]) : *low;
 #elif defined(__NetBSD__)
         *low = static_cast<char>(__classic_lower_table()[static_cast<unsigned char>(*low)]);
-#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
         *low = isascii(*low) ? static_cast<char>(__classic_lower_table()[static_cast<size_t>(*low)]) : *low;
 #else
         *low = (isascii(*low) && isupper_l(*low, _LIBCPP_GET_C_LOCALE)) ? *low-'A'+'a' : *low;
@@ -1016,7 +1016,7 @@
     return low;
 }
 
-#if defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#if defined(__EMSCRIPTEN__)
 extern "C" const unsigned short ** __ctype_b_loc();
 extern "C" const int ** __ctype_tolower_loc();
 extern "C" const int ** __ctype_toupper_loc();
@@ -1118,7 +1118,7 @@
     return _ctype+1; // internal ctype mask table defined in msvcrt.dll
 // This is assumed to be safe, which is a nonsense assumption because we're
 // going to end up dereferencing it later...
-#elif defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#elif defined(__EMSCRIPTEN__)
     return *__ctype_b_loc();
 #elif defined(_NEWLIB_VERSION)
     // Newlib has a 257-entry table in ctype_.c, where (char)0 starts at [1].
@@ -1161,7 +1161,7 @@
     return _C_toupper_tab_ + 1;
 }
 
-#elif defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#elif defined(__EMSCRIPTEN__)
 const int*
 ctype<char>::__classic_lower_table() _NOEXCEPT
 {
@@ -1173,7 +1173,7 @@
 {
     return *__ctype_toupper_loc();
 }
-#endif // __GLIBC__ || __NETBSD__ || __EMSCRIPTEN__ || defined(_LIBCPP_HAS_MUSL_LIBC)
+#endif // __GLIBC__ || __NETBSD__ || __EMSCRIPTEN__
 
 // template <> class ctype_byname<char>