I got tired of seeing the noise about XMMS' config script not being
installed making it seem like XMMS is important to QF. It might be useful,
but it's certainly not important enoug for a scary looking message.
Most of the guts of configure.ac have been moved to config.d and are then
brought in by m4_include. This will make maintaining configure.ac much easier.
Also drop use of PROGRAM and VERSION, using PACKAGE_NAME, PACKAGE_VERSION, and
on occasion, PACKAGE_STRING instead, and clean out some old files we no longer
need.