The current screened and reviewed repos both fail to build with Debian
stable's ghc-4.7.1:
$ cabal build
Building darcs-2.9.9...
Preprocessing library darcs-2.9.9...
src/Darcs/UI/Options/All.hs:1:31: Unsupported extension: LambdaCase
I don't know if that's intentional, but I think Debian stable should be
a portability baseline.
The following patch sent by Ganesh Sittampalam <ganesh@earth.li> updated issue issue2422 with
status=resolved;resolvedin=2.10.0 HEAD
* resolve issue2422: drop unneeded LambdaCase extension
Ignore-this: b51e88d25f252288f072219df5f7b2ed
It's not supported by GHC 7.4
Thanks for the report - this was unintentional and is easily fixed.
We will be supporting GHC 7.4 in the 2.10 release, but will probably
drop it from HEAD at some point in the not too distant future. By the
time 2.12 appears presumably there'll be a new Debian stable.