Patch merged into coreboot/master: c6e87f5 abuild: Build boards in parallel if possible

the following patch was just integrated into master:
commit c6e87f58ee36cc8af723f8027287158a8c91fed8
Author: Patrick Georgi 
Date:   Sat Nov 5 14:44:41 2011 +0100

abuild: Build boards in parallel if possible

Determine if xargs -P works. If yes, use that to build multiple
    boards in parallel, instead of relying on make -j X, when doing
    a full abuild run (instead of single boards).

make -j X isn't able to make use of several cores at various
    serialization points in our build process, so this change results
    in a >25% speed up for a full abuild run in my tests.

Change-Id: Id484a4211c84a3a24115278e0fbe92345f346596
    Signed-off-by: Patrick Georgi

See http://review.coreboot.org/409 for details.

-gerrit