Retitling based on: https://github.com/facebook/hiphop-php/commit/bad8a99b4ab6bd606481aea320de902878e7378e

[Using keyword instead of tracking bug for HipHop issues as requested in bug 40926 comment 5. Filter bugmail on this message.]

Note that I wrote a wikidiff2 test suite at https://github.com/MaxSem/DiffTest - it currently tests only wikidiff2_inline_diff(), but can be trivially tweaked to use wikidiff2_do_diff().

Since I was the last person to touch this extension, would be reasonable if I tried porting it:)

(In reply to Max Semenik from comment #4)

Since I was the last person to touch this extension, would be reasonable if
I tried porting it:)

That'd be awesome. Thanks for taking it on.

WIP: https://gerrit.wikimedia.org/r/#/c/117362/