Patch merged into coreboot/master: Makefile.inc: Add math macros

the following patch was just integrated into master:
commit 47abc54ec3eea1a660cfbe3bb935ef6d3ace9de0
Author: Martin Roth 
Date:   Fri Jul 3 12:54:14 2015 -0600

Makefile.inc: Add math macros

Add macros to standardize math done in the Makefiles in a posix
    compliant manner.

int-multiply takes an arbitrary list of values to multiply, the same as
    the int-addition macro.

The other macros only work on two values at a time.

Change-Id: I3b754b9bcde26f33edc4f945d5af3d5444f383c7
    Signed-off-by: Martin Roth 
    Reviewed-on: http://review.coreboot.org/10874
    Tested-by: build bot (Jenkins)
    Reviewed-by: Patrick Georgi

See http://review.coreboot.org/10874 for details.

-gerrit