sudo: allow adding extra configuration options to the bottom of sudoers

from sudoers (5):
When multiple entries match for a user, they are applied in order.
Where there are multiple matches, the last match is used (which is not necessarily the most specific match).
r-RcppArmadillo: fix download URL
r-nloptr: add missing dependency on nlopt library
r-PoweR: fix build
postgris: 1.5.1 -> 1.5.8, fixes #3389
haskell-platform: install binaries and libraries into the user environment

Fixes https://github.com/NixOS/nixpkgs/issues/2968.
haskell-ariadne: update to version 0.1.2.3
haskell-language-c: update to version 0.4.7
haskell-rethinkdb: update to version 1.15.2.0
haskell-vty-ui: update to version 1.8
libfaketime: new package

Report faked system time to programs without having to change the
system-wide time.

http://www.code-wizards.com/projects/libfaketime/
WIP: nix-prefetch-git: bring back git index (with leaveDotGit)

The git index contains timestamps. Currently we remove the index to have
deterministic output. But removing the index makes the tree "dirty". Not
good for build systems that use "git describe --dirty" to generate a
version string.

This commit runs git under the control of libfaketime (with time set to
UNIX epoch) so we don't have to delete the index and still have
deterministic output.