Adding or removing a module requires modifying both files to support
builds with and without MakeMaker. Add a comment to remind patch
authors and reviewers at the crucial moment.
Longer term, it would be nicer to maintain a single list, perhaps in a
separate file used by both build systems.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>