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/RemoteTrackingBranch.hs

@@ -77,7 +77,7 @@ makeRemoteTrackingBranchMergeCommit' commitsha importedhistory treesha = do
 	cmode <- annexCommitMode <$> Annex.getGitConfig
 	inRepo $ Git.Branch.commitTree
 			cmode
-			"remote tracking branch"
+			["remote tracking branch"]
 			[commitsha, importedhistory]
 			treesha