When .xcompile doesn't already exist, building libpayload fails because
the CC variable (et al) remain empty since .xcompile is only included
after the variables coming from there are evaluated.
Change-Id: I73f1cbced95afcff15839604fea5fd05d81bc3d3
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/18228
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
b144a34c60