Linking tpmd will fail with recent toolchains because -lgmp is passed
via LDFLAGS instead of LDLIBS. With this change -lgpm is placed at the
end of the gcc cmdline and linking tpmd succeeds again.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Committed-by: Ian Jackson <ian.jackson.citrix.com>