D-Programming-Language/deimos — comment on commit 65acb7bc0ad63649485b207ede9a59f6fcc95b61
File:  line 0
By jmdavis:

Well, it'll work. It just risks resulting in a lot of branches, and really all you want in each branch is the code for that particular header or library which the branch is for, but you get the whole repository with whatever versions the other files happen to be at. But without putting each set of related headers in their own repository, I don't see a way around that.

So yeah. It'll work. I'm just saying that it's not particularly ideal. But if you want to use branches rather than creating separate directories for each version, I don't see a way around it. And as you point out, creating separate directiories has its own set of issues.