merge-file has the same syntax as RCS merge, but supports only the
"-L" option.
For good measure, a test is added, which is quite minimal, though.
[jc: further fix for compliation errors included.]
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
