contrib/buildsystems: error out on unknown option

One time too many did this developer call the `generate` script passing
a `--make-out=<PATH>` option that was happily ignored (because there
should be a space, not an equal sign, between `--make-out` and the
path).

And one time too many, this script not only ignored it but did not even
complain. Let's fix that.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

0 files changed, 0 insertions, 0 deletions