[Haskell-beginners] Cabal build dependency using a git repo

I have a library which isn't on Hackage that I would like to use as a build dependency in another project. In Rubygems you can provide a git repository in the absence of an actual Rubygems repository. Does Cabal support something like that? I would like to specify that a particular build depend can be fetched from a given git repository rather than from Hackage and have Cabal fetch it when installing the build dependencies. I'm guessing that it's not possible because I don't see a mention of this feature anywhere. If it's not possible, how do people typically handle this problem? Git submodules?