Fixes the git installation on Darwin

[zimbatm]

git is missing the xmlto package to install. This patch just changes the allowed platforms of xmlto to "all" since it compiles fine on Darwin.

[peti]

all includes a lot more platforms than just Darwin. Are you sure all of those -- like Cygwin -- actually build?

Also, I don't see how that setting might have any effect on your ability to install git on Darwin. Hydra builds xmlto anyway when it builds git, so adding Darwin to the list of platforms doesn't change anything. What exactly is the problem that you're trying to solve?

[zimbatm]

Ok I have changed the platforms to "unix", I suspect it's going to compile find on the bsds if it's working on darwin.

When I try to install git I'm getting the following error:

$ nix-env -i git
installing `git-1.8.4.3-full'
error: user-thrown exception: the package ‘xmlto-0.0.23’ in «unknown-file» is not supported on ‘x86_64-darwin’
(use `--show-trace' to show detailed location information)

I supposed that hydra is not able to pre-build git if that dependency is failing (?).

[peti]

Ah, now I see what you mean. That issue should be fixed by commit 49db8a5.