Brief note about current status of ghc and travis-ci.
Recently made a build hook for continuous integration with travis, in one of the
repository I have in github, by following
getting started guide.
The package is requiring base >= 4.6.0, which is from ghc-7.6.*, though the
version used in travis build was base >= 4.5.*, which is from ghc-7.4.1.
There is an issue in github
mentioning ghc version used by travis builds.
It is still possible to use CPP, #ifdefs and choose the appropriate
dependency package version. Might be an opportunity to do this, though I'm not
sure the package worth for having that much maintenance efforts.