merge-trees: let caller decide whether to renormalize
Add a "renormalize" option to struct merge_options so callers can
decide on a case-by-case basis whether the merge is likely to have
overlapped with a change in smudge/clean rules. The option defaults
to the global merge_renormalize setting for now.
No change in behavior intended.
Cc: Eyvind Bernhardsen <eyvind.bernhardsen@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>