The Unix MPMs other than perchild now allow child server

The Unix MPMs other than perchild now allow child server
processes to use the accept mutex when starting as root and
using SysV sems for the accept mutex.  Previously, this
combination would lead to fatal errors in the child server
processes.  perchild can't use SysV sems because of security
issues.

translation: steal apache 1.3 code to call semop(IPC_SET) on
the semaphore to set permissions and uid/gid

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@90213 13f79535-47bb-0310-9956-ffa450edef68