Get the Perchild MPM to compile and serve pages again. There are a lot

of bugs left in this, but I am taking things one step at a time.  This
will work again.  This also gets perchild using the correct variable for
MaxRequestsPerChild

PR:     9856, 9855, 9052


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94349 13f79535-47bb-0310-9956-ffa450edef68