[SDL] Crash with SDL_FreeSurface, OS X (latest testing pieces)

[mal content]

> Hello. I've got a problem with the frameworks released a few days ago.
> My code opens an image with IMG_Load, locks the surface, reads the
> pixels, unlocks the surface and then frees it with SDL_FreeSurface -
> at this point, things crash.
>
> Here's a backtrace:
<snip>

Hmmm, upon some deep investigation, I think this one might actually
be my fault. Just to be certain:

What's in the palette struct member (in SDL_PixelFormat) if the image
is greyscale? The documentation says that palette is non-NULL for
8-bit images, but why does a greyscale image need a palette?

a1