This fix allows the trunk ldap c sdk build to be used to build the mozilla client. I was able to use this to build the mozilla 1_8 branch of thunderbird on Fedora Core 4. Addressbook and typedown addressing work fine.
The gist of the fix is to completely ignore svrcore if not specified, and to imply --with-nspr if --with-mozilla is specified. If not specified, the client build uses $(DIST)/include/nspr and $(DIST)/lib for the locations of the NSPR files.
Reviewed by Mark, Dan, Chris (Thanks!)
The newly added README.rpm explains how to build an RPM.
Running ./configure will print the list of flags and what they do.