When resolving conflicts using rebase it can be tedious having to apply the same fixes again. Turn on rerere forever.
git config --global rerere.enabled true
Now turn on diff3 conflict style resolution, forever.
git config --global merge.conflictstyle diff3
Now, to the fix ...
Make a copy of the branch to merge into.
git checkout -b mycopy
git rebase branch-i-want
Fix conflicts as they come up.
git rebase --continue
Rinse and repeat until all conflicts are gone.
git checkout original_branch
git merge branch-i-want
Hopefully rerere has saved the day completely. If not, get the correct file versions from mycopy branch.
git checkout mycopy -- file-i-want
git commit -m 'so cool'
Clean up
git branch -d mycopy