Current, the `cabal2nix` derivation contains both the executable, and a wrapper
that adds `nix` and `nix-prefetch-scripts`, which are required for some
features.
However, when calling `callCabal2nix` to create a derivation from a cabal file
at evaluation time,
these features are not actually used, but the huge closure of
`nix-prefetch-scripts` (which includes multiple vcs, as well as python and perl)
still needs to be fetched.
This commit splits cabal2nix into a lightweight version that is a standalone
static binary (`cabal2nix-unwrapped`), and a wrapper that includes the proper
dependencies in the path for full usage of the command line
utility (`cabal2nix`).
This commit also switches to the default ghc, to reduce the likelyhood of
building a different ghc when calling `callCabal2nix`.
If you actually look at the changelog for 1.4.2.1, you'll see that it
mentions that it was only intended for ghc-7.0.4, which is why it has
a dependency on an inconveniently old version of `unix`, which
is *also* hidden behind a flag, so that we can't jailbreak it (per
https://github.com/peti/jailbreak-cabal/issues/15).
So the right thing to do would appear to me to be to override our
default version to 1.4.2.0, until such time as the maintainer makes a
newer release.
`ConfigFile` was collateral damage, so unmark it broken, as well as
`MissingH` itself.
The patchs in question fail to apply against the current versoin, and
thus the package fails to build; `hasktags` is then collateral damage.
Remove reference to the patch and make sure neither package will be
marked broken going forward.
Unfortunately, we cannot compile git-annex with S3 support in an
LTS-15.x environment, because the 'aws' library hasn't updated to
version 3.x of the 'network' library [1]. I tried whether it's
possible to build git-annex with an older version of network, but
the amount of overrides we'd have to configure to accomplish that
got out of hand quickly. So I disabled aws support [2]. If you
need S3 support in git-annex, please help upstream to update
'aws' so that it builds with recent versions of 'network'.
[1] https://github.com/aristidb/aws/issues/264
[2] 1d0459f40e
