We rely on gnu make, so we can expect the jobserver to be around in
parallel builds, too. Avoids some make warnings and slightly speeds up
the build if those sub-makes are executed (eg for arm-trusted-firmware
and vboot).
Change-Id: I0e6a77f2813f7453d53e88e0214ad8c1b8689042
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/18263
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>