build: Support --disable-threads by gen-lock-obj.sh.
* configure.ac: Supply --disable-threads to gen-lock-obj.sh. Tighten the condition of using gen-lock-obj.sh for GNU/Linux. * src/gen-lock-obj.sh: Support --disable-threads.
- GnuPG-bug-id: T5296
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>