Revert "Revert "win32: remove old attempts to define snprintf _snprintf""

This reverts commit db01e438.

Original commit was correct. -- davidf
Signed-off-by: David Flynn <davidf@rd.bbc.co.uk>
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

include/vlc_common.h

@@ -783,14 +783,6 @@ VLC_EXPORT( char *, vlc_strcasestr, ( const char *s1, const char *s2 ) LIBVLC_US
 
 #   ifndef alloca
 #       define alloca _alloca
-#   endif
-
-    /* These two are not defined in mingw32 (bug?) */
-#   ifndef snprintf
-#       define snprintf _snprintf
-#   endif
-#   ifndef vsnprintf
-#       define vsnprintf _vsnprintf
 #   endif
 
 #   include <tchar.h>