This function requires libSDL 2.0.5 or higher. It looks like we don't
need to use it, and can just use the original SDL_CreateRGBSurface(),
with the masks set to 0, to trigger the default 8-bit format, which is
SDL_PIXELFORMAT_INDEX8.
Closes#7785
Note: this code path is activated by using an 8-bit blitter, like:
./bin/openttd -b 8bpp-simple