This reinstates the #includes for lib/debug.h since without that the
shader debugger fails to build. You need to manually enable it with
./autogen.sh --enable-shader-debugger and the fail only happens when
running a clean build with

$ git clean -dfx && ./autogen.sh --enable-shader-debugger && make

I have no idea what breaks, but this restores the build.

Reported by Ben Widawsky.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>