libcxx: Rename vasprintf function to __libcpp_vasprintf.

[pcc]

Summary

The language standard does not define a function with this name,
so it is part of the user's namespace. This change fixes a duplicate
symbol error that occurs when a user attempts to define a function
with this name.

[mclow.lists]

This looks fine to me.

libcxx/trunk/include/stdio.h

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
 #include_next <stdio.h>
 
 #ifdef __cplusplus
 
-// snprintf
-#if defined(_LIBCPP_MSVCRT_LIKE)
-extern "C" {
-int vasprintf(char **sptr, const char *__restrict fmt, va_list ap);
-}
-#endif
-
 #undef getc
 #undef putc
 #undef clearerr
 #undef feof
 #undef ferror
 
 #endif
 
 #endif  // _LIBCPP_STDIO_H

libcxx/trunk/src/support/win32/locale_win32.cpp

 // -*- C++ -*-
 //===-------------------- support/win32/locale_win32.cpp ------------------===//
 //
 //                     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.
 //
 //===----------------------------------------------------------------------===//
 
 #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};
 }
 
int asprintf_l( char **ret, locale_t loc, const char *format, ... )
     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 vasprintf( ret, format, ap );
+    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

libcxx/trunk/src/support/win32/support.cpp

 #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 vasprintf( char **sptr, const char *__restrict format, va_list ap )
+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));