Makefile: Rework the EXEC_SUFFIX determination

Use a conditional function for the statement. This limits the decision
to one line instead of multiple places.

Change-Id: Iee66dbc609bd5c6eb9d04b457f4508911b2e6560
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/62195
Original-Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Original-Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72298
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed