Remove flats

src/doomdef.h

src/hardware/hw_cache.c

src/hardware/hw_main.c

src/p_setup.c

src/p_setup.h

src/p_spec.c

src/p_spec.h

src/r_picformats.c

src/r_plane.c

src/r_textures.c

src/r_textures.h