Merge branch 'origin/master' into stdenv-updates.
pkgs/build-support/cabal: add support for running specific tests only via 'testTarget'

The dns packages requires this feature, because it ships two test programs: one
of them requires network access (so we cannot run it), but the other test does
not. Setting testTarget appropriately allows us to run only one of the two
suites.
haskell-dns: run only the 'spec' test suite, the 'network' test suite won't succeed on Hydra
xz: Update to 5.0.5
bash: Update to 4.2-p45
less: Update to 458

For some crazy reason, less is a stdenv dependency.
ed: Update to 1.9
dbus_cplusplus: fix build with gcc>=4.7, via Gentoo patch
coin3d: fix build with newer gcc
wesnoth: fix build, minor update, parallel builds

Yes, games are the most important things in nixpkgs...
not that I actually plan to play it anytime soon ;-)
perl: disable tests on Darwin, refactor stdenv.lib usage

There was a mysterious error, which I don't have resources to investigate:

Removing test lib/Net/hostent.t
sed: -i: No such file or directory
mu: fix build by using older texinfo
v8: fix build with newer gcc
perl: re-enable the postPatch hook on Darwin

The problem was that sed(1) variants other than GNU sed require a backup suffix
to the -i option.
perl: revert "re-enable the postPatch hook on Darwin"

This reverts commit 1778200519a18ae00751ab3015d0e665373c32f6.
Apparently, the sed -i syntax is different from what I thought, because
now the build fails on Darwin, saying:

  sed: -i.bak: No such file or directory

See http://hydra.nixos.org/build/5829944/nixlog/1/raw for more details.
ctemplate: minor update to fix build with gcc>=4.7
ois: fix build with gcc>=4.7 via a Gentoo patch
krb5: minor security update CVE-2002-2443
sonic_visualizer: fix build on newer gcc via a Gentoo patch
slibGuile: fix build via using older texinfo