Get rid of almost all uses of these definitions. They're still defined for
delinquent out-of-tree drivers, and also for the Mesa build. As well as
for miinitext.c. But largely gone.
overridden at make install time.
Remove driverdir and inputdir from pkg-config file. The directory layout of
moduledir is fixed and well known by drivers.
Fix the dri and drm build. Fix server-side DMX extension build. Make
xf4bpp use the correct version of mfbline.c for mfbseg.c. Add #ifndef
_HEADERNAME_H_/#define _HEADERNAME_H_/.../#endif to the headers.
