Update to the 20120909 snapshot of GCC 4.8.0. (Later versions have
an issue that is being in the works right now.)
Cut down the comments at the top of Makefile per recent guidance.
Revamp the handling of different languages (frontends, run-times)
by GCC to allow for orthogonal setting them in the future. 
Print the list of languages being built as part of pre-everything
and shorten the output of operating system and version there.
Inspired by: jkim