Documentation/Makefile add optional targets for l10n
The standard doc lists can be filtered to allow using the
compilation rules with translated manpages where all the pages of
the original version may not be present.
The install variable are reused in the secondary repo so that the
configured paths can be used for translated manpages too.
Signed-off-by: Jean-Noël Avila <jn.avila@free.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>