Patch merged into coreboot/master: crossgcc/Makefile.inc: Update jenkins-build-toolchain

the following patch was just integrated into master:
commit a53958098e3ba2701b071a3a7158200da6a2eddc
Author: Martin Roth 
Date:   Sat Apr 2 11:10:08 2016 -0600

crossgcc/Makefile.inc: Update jenkins-build-toolchain

Because the builders have the coreboot cross-compilers in their path,
    the XGCCPATH variable needs to be set after building the new toolchain
    before it will be used.

- Add $DEST/bin to $PATH if $DEST is set, add the default location
    for toolchain builds otherwise.  Because the jenkins build image puts
    the tools in the path, we ca
    - Add KEEP_SOURCES option to help speed up compilation (Slightly).
    - Log .xcompile for verification that the right toolchain was used.
    - Verify that test-toolchain passes.

Change-Id: I7c270dab94be7e8f801d527169767018a24986e4
    Signed-off-by: Martin Roth 
    Reviewed-on: https://review.coreboot.org/14231
    Tested-by: build bot (Jenkins)
    Reviewed-by: Patrick Georgi

See https://review.coreboot.org/14231 for details.

-gerrit