First working gcc 4.7 build

Hi, I just finished a working iMX6 build done completely with gcc 4.7.

All changes needed to make it build are committed, so most boards should compile with gcc 4.7 now (kernels might have issues, especially when built with -Werror).

0xbench results show very close to no difference between 4.6 and 4.7 builds. Binaries tend to be larger with 4.7.

Bugs seem to be largely identical as well, unfortunately 4.7 doesn't come with a fix for the live wallpaper problem.

So overall, we shouldn't run into too many problems with 4.7 - but we also shouldn't expect too much from it (yet).

ttyl bero