s390 cross-compiling code coverage

[Peter Hurley]

Occasionally, it's necessary to touch s390 code because of changes
within a subsystem, such as tty/serial.

Since changing the configs to the zEC12 march, the gcc 4.6.3 s390
cross-compiler hosted at kernel.org/pub/tools/crosstool no longer
builds any of the configs.

Would someone please add a config expected to build with that
cross-compiler? And/or point to a more recent cross-compiler?
And either confirm that one of these configs is suitable for
build coverage?

Regards,
Peter Hurley

PS - I did make sure that recent changes I've submitted for s390 drivers
     build, by hand-configuring from default_defconfig, but I'd like
     to rely on automation for build testing.