If abuild called itself recursively, the file already exists and we can spare us one evaluation of all the makefiles per recursive abuild run. Change-Id: Id3e2239354ec251c24c03c971987586deeb026c5 Signed-off-by: Nico Huber <nico.h@gmx.de> Reviewed-on: https://review.coreboot.org/c/coreboot/+/42640 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org> Reviewed-by: Reka Norman <rekanorman@chromium.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>