ediff merge wrapper

[Eliza Velasquez]

Hello,

Internally at Google, we have a wrapper performing an ediff merge with
emacs/emacsclient which blocks until the merge operation has
completed. It automatically handles edge cases such as creating a new
frame over ssh in tty mode or being invoked as an emacs subprocess. I
think it would be really useful to upstream a tool like this, given
that using emacs as a merge tool that can be invoked by software such
as mercurial or perforce can be very fiddly or have unexpected
behavior.

The biggest caveat is that the internal tool is written in golang, and
I imagine that you will want it to be rewritten to C. So before I go
and do that, I would like to gauge interest in distributing such a
wrapper alongside emacsclient and the like. What do you think?

Best,
Eliza