To use in automated tests inside containers from a tarball generated
by 'make perf-tar-src-pkg*', where testing building from a tarball
is obviously not needed, so add a 'build-test-tarball' for that case.

And don't build with gtk2 as this complicates things for cross builds
where we don't always have all the libraries a full perf build requires
available for the target arch, ditto for static builds.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>