Fix compile for GCC 4.7

Tnx zarboz & showp1984
arch/arm/Makefile: Enable pipe compiling.

Tnx zarboz & showp1984

-pipe

Use pipes rather than temporary files for communication between the various stages of
compilation. This fails to work on some systems where the assembler is unable to read
from a pipe; but the GNU assembler has no trouble.
Makefile: adding config variable for Os/O2/O3 compilation
Makefile: Added ARM and Linaro optimizations
ef47s_defconfig: Changes: optimize alot, path to compiler, localversion