Merged changeset r9285:9377 from jblum/grc into trunk, with distcheck fixes
and local modifications.

Integrates previously separate GNU Radio Companion into top-level component
'grc'. (Josh Blum)

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9378 221aa14e-8319-0410-a670-987f0aec2ac5