darcs patch: Search target bindir for dependencies in addition to $...

Hi, I found it frustrating when first using Cabal a couple weeks ago that it kept seeming to want to install alex, even after it supposedly *had* installed it. Here's a patch that will allow Cabal to find any dependencies that it installed into non-$PATH directories, so that it won't just loop forever, rebuilding and reinstalling the same things over and over again. I'm sending another patch (in a subsequent message) for cabal-install that will emit a warning whenever it installs a binary without a symlink into a directory outside the current search path. Hopefully together (or apart) these will help make Cabal more user-friendly. -steve Sun Oct 5 21:03:07 EDT 2008 Stephen Hicks * Search target bindir for dependencies in addition to $PATH. I added an extra field to the ProgramConfiguration structure to keep track of any extra paths we'd like to check that may not be in the system search path, such as the default (user) bindir for cabal-install. Now the default behavior isn't quite as important, since at least the builds won't fail (users may still wonder where their binaries are, so it should still be addressed).