Fixed a bug in detecting surface mapping changes

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40846

src/video/SDL_pixels.c

@@ -246,7 +246,12 @@ SDL_PixelFormat *SDL_ReallocFormat(SDL_Surface *surface, int bpp,
  */
 void SDL_FormatChanged(SDL_Surface *surface)
 {
-	surface->format_version++;
+	static int format_version = 0;
+	++format_version;
+	if ( format_version < 0 ) { /* It wrapped... */
+		format_version = 1;
+	}
+	surface->format_version = format_version;
 	SDL_InvalidateMap(surface->map);
 }
 /*

src/video/SDL_surface.c

@@ -106,9 +106,9 @@ SDL_Surface * SDL_CreateRGBSurface (Uint32 flags,
 	surface->hwdata = NULL;
 	surface->locked = 0;
 	surface->map = NULL;
-	surface->format_version = 0;
 	surface->unused1 = 0;
 	SDL_SetClipRect(surface, NULL);
+	SDL_FormatChanged(surface);
 
 	/* Get the pixels */
 	if ( ((flags&SDL_HWSURFACE) == SDL_SWSURFACE) ||