success with gcc-4.7.0

[ldoolitt]

I successfully built current git RockBox with gcc-4.7.0, and am running the result on my Sansa Clip+.

It took the usual small patch to gcc, which I posted to the gcc-patches list.
http://gcc.gnu.org/ml/gcc-patches/2012-06/msg00154.html
To simplify my life, I ignored the multi-arch configuration possibility, and just set up my toolchain for the arm926ej-s CPU.

A handful of compile-time warnings came out, one in particular (in chopper.c, visible when using -O2) represents a real bug.  I'll send a patch to "fix" them all to gerrit.

[saratoga]

Might be interesting to run test_codec against our sample files here:

http://download.rockbox.org/test_files/

And see if there are any performance gains/regressions. Usually though new gcc versions don't help much with older ARM processors so its not much use updating until there is some new gcc feature we want.