Also see "rpm --rebuild <package>.src.rpm".
"When invoked this way, rpm installs the named source pack_
age, and does a prep, compile and install. In addition,
--rebuild builds a new binary package. When the build has
completed, the build directory is removed (as in --clean)
and the the sources and spec file for the package are
Nothing "arcane" in that, just learning to deal with your system and read ing "man rpm".