This is a rather simple patch to add signing support to makepkg. Add a
create_signature() to makepkg, add a 'sign' BUILDENV option in makepkg.conf,
and document the changes in the makepkg.conf manpage.
Signed-off-by: Geoffroy Carrier <geoffroy.carrier@koon.fr>
Signed-off-by: Dan McGee <dan@archlinux.org>