The ecmerge documentation mentions the following form:
ecmerge --mode=diff2 $1 $2
Since git-difftool is about diffing, we should use that instead
of --mode=merge2. Likewise, this drops the $MERGED argument to
emerge, as discussed on the git list ($gmane/117930).
Signed-off-by: David Aguilar <davvid@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>