New comment by xelxebar on void-packages repository

https://github.com/void-linux/void-packages/pull/20454#issuecomment-605792586

Comment:
For some reason, `/usr/include/SDL/SDL_gfxPrimitives.h` from `SDL_gfx-devel` has
    #include <SDL.h>
whereas `SDL-devel` installs that header to `/usr/include/SDL/SDL.h`. That is why `pre_build` has that symlink hack.