Compiling darcs-2 on a fresh new Ubuntu hardy system ends with:

src/CommandLine.lhs:26:7:
    Could not find module `Text.ParserCombinators.Parsec':
      Use -v to see a list of the files searched for.

The bug is that the ./configure didn't suggest installing a package, the way
that it did for mtl, html, and quickcheck.

So I did "sudo apt-get install libghc6-parsec-dev, and now it gets past that and
stops with:

src/Darcs/Bug.lhs:9:7:
    Could not find module `Text.Regex':
      Use -v to see a list of the files searched for.

So that is the next one that configure should check for...

Okay I installed libghc6-regex-compat-dev and it proceeded with compilation.

The configure is now more explicit on what packages are missing.