When you run ./configure --help all the options regarding to LDAP are --enable-ldap and --enable-auth-ldap, while it does not mention that you need --with-ldap to make APR build with LDAP support.
*** Bug 19394 has been marked as a duplicate of this bug. ***
Created attachment 10006 [details] Make configure emit a useful error when user enables mod_ldap or mod_auth_ldap but does not enable LDAP in apr-util
The patch I just attached causes configure to fail with a fatal error if the user requests mod_auth_ldap or mod_ldap but does not use an LDAP-capable apr-util. Since most people who wouldn't then know what to do will use the included apr-util, the error message tells them to use --with-ldap, which will solve their problem. I modeled the test after the test mod_auth_digest uses. To make the test simple, I made a small change to APR_CHECK_APR_DEFINE: if given an second argument, that macro now includes the header file so given instead of apr.h. This should not break existing usage. Please let me know if a different solution seems superior. Note that this does not fix the issue as the original post describes it since mod_[auth_]ldap only requires --with-ldap if you use the in-tree apr-util sources. I have created a new bug (#26240) that proposes a solution to the problem of incomplete option listing.
Both mod_ldap and mod_auth_ldap will emit this error message if ldap is missing from apr-util: #error mod_ldap requires APR-util to have LDAP support built in I will update this error message to tell the user what to do, as this message is not entirely clear.
*** Bug 27815 has been marked as a duplicate of this bug. ***
The newest versions httpd (2.2.12) and apr-utils (1.3.37) seem to have a regression, regarding to the previous version, as apu-1-config does NO longer default to showing the ldap-libs. httpd's --with-ldap, doesn't honor this change either, and doesn't supply it. I have created a apu-ldap-config: #!/bin/bash $_prefix/apu-1-config $@ --ldap-libs BUT, both, setting APU_CONFIG in EVN, and supplying --with-apr-util to it's full path is being IGNORED.
Igor, I suggest taking your httpd 2.2.12/APR-Util issue 1.3.7 issue to the user support list to sort out what is going on. It is apparently not the issue tracked by this bug.
With respect to #6, Igor, open a new bug, if you confirm this is true of the bundled apr-util (which should be 1.3.8), and please report more specific details.