pgsql: Link libpq with libgssapi if configure finds it, as required by

Log Message:
-----------
Link libpq with libgssapi if configure finds it, as
required by at least NetBSD.

Markus Schaaf

Modified Files:
--------------
pgsql/src/interfaces/libpq:
Makefile (r1.167 -> r1.168)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/Makefile?r1=1.167&r2=1.168)