libcxx: Rename vasprintf function to __libcpp_vasprintf.

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.

Differential Revision: https://reviews.llvm.org/D42405

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@323237 91177308-0d34-0410-b5e6-96231b3b80d8

include/stdio.h

@@ -109,13 +109,6 @@ void perror(const char* s);
 
 #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

src/support/win32/locale_win32.cpp

@@ -13,6 +13,8 @@
 #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
@@ -105,7 +107,7 @@ int asprintf_l( char **ret, locale_t loc, const char *format, ... )
 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)

src/support/win32/support.cpp

@@ -19,7 +19,7 @@
 // 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.