http://cgit.freedesktop.org/mesa/mesa/commit/?id=264e6dad28e64755dc1580abdbb4e339c3439883

introduce the regression:

make[4]: Entering directory `/build/src/mesa-git/src/gallium/drivers/r600'
  CC       r600_asm.lo
In file included from r600_pipe.h:33:0,
                 from r600_formats.h:5,
                 from r600_asm.c:25:
r600_llvm.h:7:25: fatal error: radeon_llvm.h: No such file or directory
compilation terminated.
make[4]: *** [r600_asm.lo] Error 1
make[4]: Leaving directory `/build/src/mesa-git/src/gallium/drivers/r600'
make[3]: *** [all-recursive] Error 1
make[3]: Leaving directory `/build/src/mesa-git/src/gallium/drivers'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/build/src/mesa-git/src/gallium'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/build/src/mesa-git/src'
make: *** [all-recursive] Error 1

because USE_R600_LLVM_COMPILER is defined, not HAVE_GALLIUM_COMPUTE