Link dri drivers with mesa or dricore libtool library

Link dri drivers with mesa or dricore libtool library

Now mesa/drivers/dri is converted to automake, we want to update DRI_LIB_DEPS
so that we link with the libmesa or libdricore libtool library, as appropriate.

However, this is complicated by the fact that gallium/targets is not (yet)
converted, so we can't share the DRI_LIB_DEPS autoconf variable with that anymore.

Add an additional autoconf variable GALLIUM_DRI_LIB_DEPS, which is now used in
gallium/targets/Makefile.dri, to link with the libdircore or libmesa native library.

v2: libdricore$VERSION.a needs to be libdricore$(VERSION).a

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Matt Turner <mattst88@gmail.com>