Backed out commit 80ce90dbc266, this causes Visual Studio build failure on buildbot

src/stdlib/SDL_stdlib.c

@@ -275,11 +275,8 @@ int SDL_tolower(int x) { return ((x) >= 'A') && ((x) <= 'Z') ? ('a'+((x)-'A')) :
 
 #ifndef __FLTUSED__
 #define __FLTUSED__
-/* the multithreaded runtime already includes libcmt.lib - and this symbol is in there. */
-#ifndef _MT
 __declspec(selectany) int _fltused = 1;
 #endif
-#endif
 
 /* The optimizer on Visual Studio 2005 and later generates memcpy() calls */
 #if (_MSC_VER >= 1400) && defined(_WIN64) && !defined(_DEBUG)