Cherry-pick upstream r252457

include/__locale

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
@@ skipping 23 matching lines @@
 // @LOCALMOD-START
 #elif defined(_NEWLIB_VERSION)
 // FIXME: replace all the uses of _NEWLIB_VERSION with __NEWLIB__ preceded by an
 // include of <sys/cdefs.h> once https://sourceware.org/ml/newlib-cvs/2014-q3/msg00038.html
 // has had a chance to bake for a bit.
 #include <support/newlib/xlocale.h>
 // @LOCALMOD-END
 #elif (defined(__GLIBC__) || defined(__APPLE__)      || defined(__FreeBSD__) \
     || defined(__EMSCRIPTEN__) || defined(__IBMCPP__))
 # include <xlocale.h>
+#elif defined(_LIBCPP_HAS_MUSL_LIBC)
+# include <support/musl/xlocale.h>
 #endif // __GLIBC__ || __APPLE__ || __FreeBSD__ || __sun__ || __EMSCRIPTEN__ || __IBMCPP__
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 class _LIBCPP_TYPE_VIS locale;
 
@@ skipping 272 matching lines @@
     return _VSTD::use_facet<_VSTD::collate<_CharT> >(*this).compare(
                                        __x.data(), __x.data() + __x.size(),
                                        __y.data(), __y.data() + __y.size()) < 0;
 }
 
 // template <class charT> class ctype
 
 class _LIBCPP_TYPE_VIS ctype_base
 {
 public:
-#ifdef __GLIBC__
+#if defined(__GLIBC__)
     typedef unsigned short mask;
     static const mask space  = _ISspace;
     static const mask print  = _ISprint;
     static const mask cntrl  = _IScntrl;
     static const mask upper  = _ISupper;
     static const mask lower  = _ISlower;
     static const mask alpha  = _ISalpha;
     static const mask digit  = _ISdigit;
     static const mask punct  = _ISpunct;
     static const mask xdigit = _ISxdigit;
     static const mask blank  = _ISblank;
 #elif defined(_WIN32)
     typedef unsigned short mask;
     static const mask space  = _SPACE;
     static const mask print  = _BLANK|_PUNCT|_ALPHA|_DIGIT;
     static const mask cntrl  = _CONTROL;
     static const mask upper  = _UPPER;
     static const mask lower  = _LOWER;
     static const mask alpha  = _ALPHA;
     static const mask digit  = _DIGIT;
     static const mask punct  = _PUNCT;
     static const mask xdigit = _HEX;
     static const mask blank  = _BLANK;
 #elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__EMSCRIPTEN__) || defined(__NetBSD__) || defined(__ANDROID__)
 #ifdef __APPLE__
     typedef __uint32_t mask;
 #elif defined(__FreeBSD__)
     typedef unsigned long mask;
-#elif defined(__EMSCRIPTEN__) ||  defined(__NetBSD__)
+# elif defined(__EMSCRIPTEN__) || defined(__NetBSD__) || defined(_LIBCPP_HAS_MUSL_LIBC)
     typedef unsigned short mask;
 #elif defined(__ANDROID__)
     typedef unsigned char mask;
 #endif
     static const mask space  = _CTYPE_S;
     static const mask print  = _CTYPE_R;
     static const mask cntrl  = _CTYPE_C;
     static const mask upper  = _CTYPE_U;
     static const mask lower  = _CTYPE_L;
     static const mask alpha  = _CTYPE_A;
@@ skipping 31 matching lines @@
     static const mask cntrl  = _C;
     static const mask upper  = _U;
     static const mask lower  = _L;
     static const mask alpha  = _U | _L;
     static const mask digit  = _N;
     static const mask punct  = _P;
     static const mask xdigit = _X | _N;
     static const mask blank  = _B;
 // @LOCALMOD-END
 #else  // __GLIBC__ || _WIN32 || __APPLE__ || __FreeBSD__ || __EMSCRIPTEN__ || __sun__
+#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;
     static const mask upper  = 1<<3;
     static const mask lower  = 1<<4;
     static const mask alpha  = 1<<5;
     static const mask digit  = 1<<6;
     static const mask punct  = 1<<7;
     static const mask xdigit = 1<<8;
     static const mask blank  = 1<<9;
@@ skipping 201 matching lines @@
 
     static locale::id id;
 
 #ifdef _CACHED_RUNES
     static const size_t table_size = _CACHED_RUNES;
 #else
     static const size_t table_size = 256;  // FIXME: Don't hardcode this.
 #endif
     _LIBCPP_ALWAYS_INLINE const mask* table() const  _NOEXCEPT {return __tab_;}
     static const mask* classic_table()  _NOEXCEPT;
-#if defined(__GLIBC__) || defined(__EMSCRIPTEN__)
+#if defined(__GLIBC__) || defined(__EMSCRIPTEN__) || defined(_LIBCPP_HAS_MUSL_LIBC)
     static const int* __classic_upper_table() _NOEXCEPT;
     static const int* __classic_lower_table() _NOEXCEPT;
 #endif
 #if defined(__NetBSD__)
     static const short* __classic_upper_table() _NOEXCEPT;
     static const short* __classic_lower_table() _NOEXCEPT;
 #endif
 
 protected:
     ~ctype();
@@ skipping 824 matching lines @@
 protected:
     ~numpunct_byname();
 
 private:
     void __init(const char*);
 };
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP___LOCALE