Apparently we didn't have a wrap find module for it before. Add one,
and add special support to handle a Gentoo broken Config file which is
exported by an autotools build of harbuzz.
Change-Id: I83cbeb817caf2610104c16713d4eac6ab6f8c63b
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Qt CMake Build Bot
