tests: Put a work around to tests/random for macOS.
* configure.ac [*-apple-darwin*] (USE_POSIX_SPAWN_FOR_TESTS): New. * tests/random.c [USE_POSIX_SPAWN_FOR_TESTS] (run_all_rng_tests): New.
Cherry-pick master commit of:
9769b40b54cf010a0c41c4ab05a7a88e17d70613
- GnuPG-bug-id: T5159
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>