Merged revision 3458 from SDL 1.2, fixed Borland C alloca() prototype

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%402649

include/SDL_stdinc.h

@@ -212,6 +212,8 @@ extern DECLSPEC void SDLCALL SDL_free(void *mem);
 #  define alloca _alloca
 # elif defined(__WATCOMC__)
 #  include <malloc.h>
+# elif defined(__BORLANDC__)
+#  include <malloc.h>
 # elif defined(__DMC__)
 #  include <stdlib.h>
 # elif defined(__AIX__)