cc/gcc: backport upstream patches for GCC bug 54369

See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54369 for more information
This bug has a serious effect on Linux/MIPS and SPARC kernel builds.

Add the fix for these versions of gcc: 4.6.0, 4.6.2, 4.6.3, and 4.7.0.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

 # Compute sparc-specific values

 CT_DoArchTupleValues() {

     # That's the only thing to override

     if [ "${CT_ARCH_64}" = "y" ]; then

         CT_TARGET_ARCH="${CT_ARCH}64"

     fi

 }