Why would you want to use such a limited diff tool at all? Personally, I use the best diff tool that I can find and so far that's BeyondCompare from Scooter Software.
Personally, I pay for the best tools because they're worth the money. For that tool in particular, I paid $60 over 3 or 4 years ago. It's practically nothing compared to some of the other tools that we use.
I wonder if they were slow on updating their site because of Sourcetree, which I personally love (especially since it is a cross-platoform [Mac/Win] GUI client).
https://github.com/torvalds/linux/commit/b0b9b3df27d100a975b...
syntax highlighting would be like this, where keywords, function calls, and variables are all different colors.
I just checked our Bitbucket. There's no syntax highlighting for any of our used languages for diffs. There is no option to enable or disable it. When you do a search for it, it's still an open issue in BitBucket's public issue tracker[0].
If you've got some wizardry working that isn't an external script, hook it up.
[0]: https://bitbucket.org/site/master/issues/8673/add-syntax-hig...