gcc-4.7: Backport libgcc fixes to appease the new build sequence

gcc-4.7: Backport libgcc fixes to appease the new build sequence

This makes the libgcc builds identical when done with gcc-cross-initial
or final gcc-cross. Since eglibc only sees gcc-cross-initial it is
important that the final libgcc that appears on root file system is same
as the one against which eglibc was built.

(From OE-Core rev: bd0ab094d6c36b55848e23e63b96587773299a7f)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>