[PATCH] makefiles: use configured name for -ldrm* where possible

[PATCH] makefiles: use configured name for -ldrm* where possible

For precise lts support I had to do some magic with the library names, which works fine
as long as the libraries from pkg-config are used.

The parts with src/gallium/targets/va-*/Makefile will not apply on the master branch,
but do apply to the 9.0 branch.

NOTE: This is a candidate for the 9.0 branch.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Matt Turner <mattst88@gmail.com>
(cherry picked from commit 4f0537e645f9c34e305f2808c70eafbbc1c7689c)