I am on Windows 10, using GNU grep 2.10.
Update: The question has been answered, but I now realize the premise of this question is wrong, because it turns out I must've had some typo that I didn't see even after re-reading my commands multiple times. There is nothing wrong with the grep included in nuwen.net. Thank you Stephan T. Lavavej. I will keep this answer up because it still taught me something that the previous question (linked below) did not.
Original question as follows:
As explained in this question, multiple --include statements can be used to search multiple file extensions.
However, I experienced an issue when I have multiple file extensions that only differ in capitalization.
grep -ri "foo" --include="*.h" --include="*.H" .
The above command will only search through .h files, and not .H files.
grep -ri "foo" --include="*.H" --include="*.h" .
The above command now will only search through .H files, and not .h files.
So apparently, it is only processing the first --include argument because it considers the second to be a duplicate, but then it doesn't search both .H and .h.
My question is: How do I get GNU grep on Windows to search both (and only both) file extensions?