cabal sdist trouble with GHC from head

[Sven Panne]

2014-10-30 17:20 GMT+01:00 Austin Seipp <austin at well-typed.com>:
> [...] So this just means that Cabal isn't necessarily *future compatible*
> with future GHCs - they may change the package format, etc. But it is
> backwards compatible with existing ones.

OK, that's good to know. To be sure, I've just tested Cabal head + GHC
7.8.3, and it works. But as I've mentioned already, there seems to be
*no* Cabal version which works with GHC head:
https://travis-ci.org/haskell-opengl/StateVar/builds/39533448 Is this
known to the Cabal people?