Broken linkage rule for Clang builds on one side of a
branch. Hence refactor out common rules from branch.
Change-Id: I00e5a2f5f9af1b7882a453caebb378ef74d2d51e
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7425
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)