Add GHC-7.8.1-rc2.
libproxy: attempt to fix build on Darwin

It seems it won't compile with too old compilers.
libvirt: Clean up nix file, update meta
libvirt-python: Update from 1.2.0 to 1.2.2
move windowManager.xbmc to desktopManager.xbmc
Merge pull request #1921 from kosmikus/ghc-7.8.1

Add GHC-7.8.1-rc2.
Add phpfpm NixOS service module
phpfpm module: Make extraConfig and poolConfigs mergeable by switching option type to types.lines