[PATCH 0/2] Introducing git-run-with-user-path program.

I've polished the driver part a bit more, so that it can do something similar to "git-ls-files --others" can do, but with the (to-be-defined) "ignore rules Porcelain layers would agree upon".

 [PATCH 1/2] Introduce git-run-with-user-path helper program.
 [PATCH 2/2] Add sample ignore logic to git-run-with-user-path command.

The first one adds a path canonicalization helper with path ignore hooks but no ignore logic implementation (it passes everything that passes verify_path()). The second one adds a sample ignore logic implementation using PCRE.

Although the second one is done primarily as an example and to start a mailing list discussion, it should be also safe to merge if you decide to take patch 1, because the logic is used only by git-run-with-user-path which is a new program. no Porcelain uses right now.