How can I do case insensitive git diffing while also doing `git diff --color`?

Question

Is it possible to do a case insensitive git diff while also doing git diff --color-words? Or do I need to use an external diff program while doing

Answer 1

I figured out a way to perform case-insensitive diff, although not with the --color-word option as the OP asked for. See my answer to my own question.

Answer 2

GIT_EXTERNAL_DIFF='diff -ipu "$2" "$5" #' git diff --ext-diff

Or, in a nicer fashion without the # hack I used there:

echo 'diff -ipu "$2" "$5"' >myscript; chmod a+x myscript;
GIT_EXTERNAL_DIFF='./myscript' git diff --ext-diff

I agree it would be nicest if git-diff would just have an -i option...