crossgcc: Add clang support

Add a new option -C|--clang to buildgcc to build a clang based
toolchain as opposed to a gcc based toolchain. This toolchain
comes with the required patches needed to successfully build
coreboot, and also with clang's famous scan-build script.

Change-Id: I1aea7cd6002edc4f3bb2b46dc1f69a212ad18f77
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/10415
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
6 files changed