gcc: Add --enable-linker-build-id

gcc: Add --enable-linker-build-id

See https://fedoraproject.org/wiki/Releases/FeatureBuildId for the
benefits this brings.  As far as I can tell from searching the
discussion archives, there doesn't appear to be a reason not to enable
this, and the benefits are real.

Both the Red Hat Enterprise Linux 6, all Fedora, and Ubuntu Quantal
GCC builds are configured with this on.  I plan to use it in
gnome-ostree.

(From OE-Core rev: f3be2b1e5e100a953d6d7fbbb19a77a5c4d547e1)

Signed-off-by: Colin Walters <walters@verbum.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>