Suppose there's a subdirectory named `MÜNCHEN` in the current directory, then tab-completion won't recognize this directory, when `cd münchen` + [tab] is given.

I noticed this behavior when attempting to cd the given directory (with tab autocomletion), and while doing the same with `rm -r`.

I assume, it's a zsh-wide issue due to broken case-insensitive matching umlauts.

I'd like to provide some patch, but I was unable to figure out, where the bug is caused.

Thanks,
Luis