Merge r1919740 from trunk:

* shmem/unix/shm.c (apr_shm_perms_set): Omit the POSIX shm
  implementation on MacOS (falling through to ENOTIMPL instead), since
  it is either failing or hanging in testing.

See https://lists.apache.org/thread/1gj7j8h0nxlly2j2gnrbh6m7sy4o0fob

(already present on 1.7.x)


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.8.x@1920080 13f79535-47bb-0310-9956-ffa450edef68

shmem/unix/shm.c

@@ -709,7 +709,9 @@ APR_PERMS_SET_IMPLEMENT(shm)
         return errno;
     }
     return APR_SUCCESS;
-#elif APR_USE_SHMEM_MMAP_SHM
+#elif APR_USE_SHMEM_MMAP_SHM && !defined(DARWIN)
+    /* ### This hangs or fails on MacOS, so skipping this for the
+     * ENOTIMPL case there - unclear why or if that's fixable. */
     apr_shm_t *shm = (apr_shm_t *)theshm;
     const char *shm_name;
     int fd;