plus several 71, 80 and 90 versions in the "C:\Program Files (x86)" tree.
> emacs -Q -batch --eval "(princ (directory-files \".\" nil \"?*\\.c\\'\"))"
> If quoted arguments work "as I'd expect" (i.e. quotes are removed,
> unless escaped by a backslash, in which case the backslash is removed
> and the quote stays), then this command should display the list of all
> *.c files in the directory where you invoke this command.