* os/unix/os.h: Define AP_NEED_SET_MUTEX_PERMS.

* modules/mappers/mod_rewrite.c, modules/ssl/ssl_engine_mutex.c: Use
AP_NEED_SET_MUTEX_PERMS to determine whether unixd_set_*_mutex_perms
calls are necessary.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@105411 13f79535-47bb-0310-9956-ffa450edef68