Fix virtualenvwrapper shell scripts
inkscape: add python to the PATH, fixes #3449
glib-tested: fix running tests
Fix NixOS evaluation on i686-linux
libpar2: Update to 0.4
nzbget: Update to 13.0
GHC 7.6 and earlier cannot compile aeson 0.8.x.
emacs: Fix building on Darwin with recent versions of GCC

This gets rid of the "unexec: unrecognized section __static_data in
__DATA segment" error while dumping Emacs.
emacs: On Darwin, don't depend on gconf and cairo
GHC 7.6.x required scientific 0.2.x to build aeson 0.7.x.
Merge pull request #3507 from jochu/nix-update-nzbget

Update nzbget (13.0) and libpar2 (0.4)
gnuplot: Reduce dependency bloat a bit
nixos/znc: add option to add module packages to znc

Besides that add option for extra znc config and fix a lot of stuff
GHC 7.6.x requires older attoparsec to build with aeson 0.7.x.
gnuplot: Use default compiler on Darwin
redis: Build with default gcc
Refactoring
Merge pull request #3495 from geerds/virtualenvwrapper

Fix virtualenvwrapper shell scripts
cmake: Fix setup hook on bash < 4.0

This matters in nix-shell and stdenvNative on Darwin.

Fixes #3204.
Hack to fix llvm/clang build on Darwin

(Or at least restore it to the same level as brokenness as before the
staging merge. I.e. it depends on gcc-apple, which doesn't build on
standard 10.9 systems.)