handle mod_ldap/mod_authnz_ldap, along with tiny infrastructure

for modules whose main source doesn't match the module name
(i.e., util_ldap.c vs. mod_ldap)

please let mod_ldap be the only user of that support foreverandever


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1520819 13f79535-47bb-0310-9956-ffa450edef68