the address of a function argument which triggers a gcc ICE on sparc64
resulting in libdrm_radeon not being built as reported by naddy.
kettenis pointed out that while other architectures probably spill the
argument onto the stack this is likely not the case on register window
architectures like SPARC and suggested passing a pointer as an argument
instead which avoids the ICE and allows the drm libraries requiring
atomics to build on sparc64 again.
ok kettenis@ matthieu@
Now that xenocara has been made clean with respect to using kernel headers
instead of those provided with libdrm, remove the copy of the headers included
here. Since it is now very simple, move it over to using standard bsd makefiles
instead of autoconf.
ok matthieu@
