The bdwgc recipe uses a version of libatomic that fails when building in Thumb
mode. This has been fixed upstream already. The
pulseaudio/libatomics-ops_1.2.bb has the same issue and sets the
ARM_INSTRUCTION_SET to "arm" (probably until a new version gets pulled in).
This patch applies the same workaround to the bdwgc/bdwgc_20110107.bb recipe.