Patch merged into coreboot/master: build system: don't let a broken .xcompile linger in the tree

the following patch was just integrated into master:
commit bdb4af8bfd1eedb4cd58624b8dfdbc13f82c3654
Author: Patrick Georgi 
Date:   Thu Nov 19 09:53:04 2015 +0100

build system: don't let a broken .xcompile linger in the tree

If the xcompile script fails (with an error message), we should delete
    the generated file so that later builds try to regenerate the file and
    re-report the problem if it still persists.

Change-Id: I70ec37ca8ccb8ed3d8d0da48b326f5e0d722f314
    Signed-off-by: Patrick Georgi 
    Reviewed-on: http://review.coreboot.org/12473
    Tested-by: build bot (Jenkins)
    Reviewed-by: Paul Menzel 
    Reviewed-by: Martin Roth

See http://review.coreboot.org/12473 for details.

-gerrit