They sure as hell aren't perfect, but they allow you to do:
./git-pull-script {other-git-directory}
to do the initial merge, and if that had content clashes, you do
merge-cache ./git-merge-one-file-script -a
which tries to auto-merge. When/if the auto-merge fails, it will
leave the last file in your working directory, and you can edit
it and then when you're happy you can do "update-cache filename"
on it. Re-do the merge-cache thing until there are no files left
to be merged, and now you can write the tree and commit:
write-tree
commit-tree .... -p $(cat .git/HEAD) -p $(cat .git/MERGE_HEAD)
and you're done.
