arch/s390: cleanups

Don't select unneeded config knobs. Don't select non-existing config knobs.
Use the "no patch" config knob, instead of pointing to an non-exiting local
patch dir. Simplify the tuple-related scripts. Update the samples.

config/global: enable not using patches at all

It can be needed to build a toolchain with no patch at all.

arch: add s390 and s390x architectures and samples

Merge.

libc/glibc: allow more than one line in configparms

samples: update the armeb-unknown-linux-gnueabi sample to use glibc-2.10.1

libc/glibc: add 2.10.1

Woo... It seems the glibc guys finally decided that tarballs
were not deprecated, in fact.

The patchset was vampirised from Gentoo (kudos, guys!), and
applies to glibc+ports, so that's why it's been added as a
patchset against ports, not against glibc.

scripts: add a new helper script to easily rediff a patchset

scripts: be POSIXly correct in helper scripts

Fix helper scripts to be POSIXly correct: don't expect '.' (the dot
builtin) to search CWD if it is not in $PATH.

scripts: output renumbered patches in a new directory

When renumbering patches, the original patches get removed and replaced
with the new ones. This can be annoying to loose the original patches.
Fix this by putting the new patchs in a directory of their own.