Fix building t-lock for WIN32
* tests/t-lock.c (external_lock_test_init, external_lock_test_lock) (externel_lock_test_unlock, external_lock_test_destroy) (nonce_thread, get_rand, pick_account, pick_value, revision_thread) (accountant_thread): Build also if _WIN32 defined in addition to HAVE_PTHREAD.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>