Use plain extern instead of extern "C" for vsnprintf declaration when not

compiling as C++.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@32164 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/wxchar.h

@@ -768,7 +768,11 @@ WXDLLIMPEXP_BASE bool wxOKlibc(); /* for internal use */
    headers, so we need to declare it ourselves to be able to use it.
  */
 #if defined(HAVE_VSNPRINTF) && !defined(HAVE_VSNPRINTF_DECL)
+#ifdef __cplusplus
     extern "C"
+#else
+    extern
+#endif
     int vsnprintf(char *str, size_t size, const char *format, va_list ap);
 #endif /* !HAVE_VSNPRINTF_DECL */