multiple -m

sync, assist, import: Allow -m option to be specified multiple times, to
provide additional paragraphs for the commit message.

The option parser didn't allow multiple -m before, so there is no risk of
behavior change breaking something that was for some reason using multiple
-m already.

Pass through to git commands, so that the method used to assemble the
paragrahs is whatever git does. Which might conceivably change in the
future.

Note that git commit-tree has supported -m since git 1.7.7. commitTree
was probably not using it since it predates that version. Since the
configure script prevents building git-annex with git older than 2.1,
there is no risk that it's not supported now.

Sponsored-by: Nicholas Golder-Manning on Patreon

Annex/Branch.hs

@@ -945,9 +945,9 @@ rememberTreeishLocked treeish graftpoint jl = do
 	addedt <- inRepo $ Git.Tree.graftTree treeish graftpoint origtree
 	cmode <- annexCommitMode <$> Annex.getGitConfig
 	c <- inRepo $ Git.Branch.commitTree cmode
-		"graft" [branchref] addedt
+		["graft"] [branchref] addedt
 	c' <- inRepo $ Git.Branch.commitTree cmode
-		"graft cleanup" [c] origtree
+		["graft cleanup"] [c] origtree
 	inRepo $ Git.Branch.update' fullname c'
 	-- The tree in c' is the same as the tree in branchref,
 	-- and the index was updated to that above, so it's safe to