Add system header pragma to BSD locale fallback headers.

This prevent leaking warnings to the user about use of C++11
extensions in C++03.

llvm-svn: 309917

libcxx/include/__bsd_locale_defaults.h

@@ -15,6 +15,10 @@
 #ifndef _LIBCPP_BSD_LOCALE_DEFAULTS_H
 #define _LIBCPP_BSD_LOCALE_DEFAULTS_H
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #define __libcpp_mb_cur_max_l(loc)                          MB_CUR_MAX_L(loc)
 #define __libcpp_btowc_l(ch, loc)                           btowc_l(ch, loc)
 #define __libcpp_wctob_l(wch, loc)                          wctob_l(wch, loc)

libcxx/include/__bsd_locale_fallbacks.h

@@ -18,6 +18,10 @@
 #include <stdarg.h>
 #include <memory>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 inline _LIBCPP_ALWAYS_INLINE