Build breaks if MANPATH contains multiple directories

[sshambar]

The configure script doesn't correctly handle locating the mandir directory, and uses the MANPATH environment variable directly - which breaks if MANPATH is a true path with multiple path entries.

I've updated configure to handle this case, and added support for a --mandir parameter, and updated the rpm spec file to use it (passing the system _mandir value).

I also updated the spec file to generalize the handling of httpd conf and module directories, and added support for some of the fedora macros for documentation (which I believe are used in other distributions).