Re: change of git-diff-tree and symlinks

KS> Ok, works again. Any reason not to mark it as 'M'? It's easyly to KS> distinguish between a content change and a mode change by looking if KS> the sha has changed.

I'd need some time to think about this in the evening (I'm at work now) but I think Linus did '?' as an interim measure. I suspect 'M' would work just as well without introducing a new class 'T', but on the other hand having them distinct would be easier for people who read diff-raw format, so my knee-jerk reaction is that we should use 'T'. It's the same reasoning to have N, D, and U --- they can be gleaned by looking at mode and sha fields and there is no need to mark them any differently but surely marking them the way we do now is much nicer.

More importantly I need to double check that diffcore stuff including rename/copy are doing the right thing about type changes. If some of them are throwing type-change pair away under certain obscure conditions, then tweaking the part Linus added the '?' is too late to remedy the situation.