Add an RPM spec file.

Automatically set the version via configure.

Signed-off-by: Benoit Sigoure <tsunanet@gmail.com>
Make it easier to build an RPM from source.

Add an `rpm' target to the Makefile that creates a tarball of the
current sources, and uses it to build an RPM.  Also fix various
issues to be able to build on Fedora and neuter various RPM macros
that are sometimes overridden and make life unnecessarily painful.