ITS#8504 Fix prev commit: mc_error, #ifdef SIGPIPE

Never clear mc_error, we could lose a failure in the other thread.

libraries/liblmdb/mdb.c

@@ -9787,17 +9787,17 @@ mdb_env_copythr(void *arg)
 #define DO_WRITE(rc, fd, ptr, w2, len)	rc = WriteFile(fd, ptr, w2, &len, NULL)
 #else
 	int len;
-	sigset_t set;
 #define DO_WRITE(rc, fd, ptr, w2, len)	len = write(fd, ptr, w2); rc = (len >= 0)
-
+#ifdef SIGPIPE
+	sigset_t set;
 	sigemptyset(&set);
 	sigaddset(&set, SIGPIPE);
+	if ((rc = pthread_sigmask(SIG_BLOCK, &set, NULL)) != 0)
+		my->mc_error = rc;
+#endif
 #endif
 
 	pthread_mutex_lock(&my->mc_mutex);
-#ifndef _WIN32
-	my->mc_error = pthread_sigmask(SIG_BLOCK, &set, NULL);
-#endif
 	for(;;) {
 		while (!my->mc_new)
 			pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
@@ -9811,8 +9811,11 @@ again:
 			DO_WRITE(rc, my->mc_fd, ptr, wsize, len);
 			if (!rc) {
 				rc = ErrCode();
-#ifndef _WIN32
+#if defined(SIGPIPE) && !defined(_WIN32)
 				if (rc == EPIPE) {
+					/* Collect the pending SIGPIPE, otherwise at least OS X
+					 * gives it to the process on thread-exit (ITS#8504).
+					 */
 					int tmp;
 					sigwait(&set, &tmp);
 				}