[PATCH 0/2] diff-tree/diff-cache helper

I use a set of small scripts [*1*] directly on top of the core git, which needed to make patches out of diff-tree and diff-cache output. Its output is compatible with what show-diff produces.

Since this helper program would be generally useful for other wrapper layer programs like Cogito, I am submitting it in two parts. The first part is to rip out the external diff program interface part out of show-diff.c and moving it into a common library. The second part introduces the diff-tree-helper program.

[Footnotes]

*1* This is found at http://members.cox.net/junkio/