Patch merged into coreboot/master: buildgcc: Use $(CURDIR) instead of $(PWD)

the following patch was just integrated into master:
commit 9b1936dc829ef1c0fd32368ecbce432f1b05cffb
Author: Stefan Reinauer 
Date:   Tue Mar 1 12:55:47 2016 -0800

buildgcc: Use $(CURDIR) instead of $(PWD)

coreboot's top level Makefile does the same, so let's stay consistent.

Change-Id: I9e995f3ecadd05d6fbfda64b45dee3a9900d9189
    Signed-off-by: Stefan Reinauer 
    Reviewed-on: https://review.coreboot.org/13869
    Tested-by: build bot (Jenkins)
    Reviewed-by: Martin Roth

See https://review.coreboot.org/13869 for details.

-gerrit