gallium/targets: Make use of prebuilt libdricommon.la.

libdricommon.la is available whenever a non swrast driver is built.
All the classic dri drivers make use of the prebuild library but all
of the gallium ones rebuild it explicitly.

While we're here gallium/{llvm,soft}pipe does not require HAVE_COMMON_DRI
thus do not set in during configure.

v2: [Emil] Add commit message and drop HAVE_COMMON_DRI from configure.ac
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
mesa/drivers: drop HAVE_*_DRI from individual makefiles

The mesa/drivers/dri/Makefile.am already guards the individual
targets/subdirs with HAVE_*_DRI before including them. Thus making
the additional check within each Makefile.am unnecessary.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
gallium/radeon: drop unused variable LIBGALLIUM_LIBS

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
r600: use NEED_RADEON_LLVM over R600_NEED_RADEON_GALLIUM

libllvmradeon.la is available whenever NEED_RADEON_LLVM is set, using
R600_NEED_RADEON_GALLIUM is rather ambiguous and unnecessary. Drop it
in favour of NEED_RADEON_LLVM.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
softpipe: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
rbug: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
llvmpipe: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
trace: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
freedreno: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
identity: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
noop: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
galahad: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/dri: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/dri/sw: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/xorg: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/vega: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/glx: consolidate C sources list into Makefile.sources

Move glx/{,xlib/}Makefile.am to preserve file list

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/egl: consolidate C sources lists into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
winsys/i915/sw: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
winsys/nouveau/drm: consolidate C sources list into Makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>