Merge conflicts are reported relative to root not cwd

$ cd t/
$ git merge ...
...
Auto-merging builtin/submodule--helper.c
Auto-merging builtin/fetch.c
CONFLICT (content): Merge conflict in builtin/fetch.c
Auto-merging builtin/clone.c
Auto-merging README.md
...

It should say ../builtin/fetch.c IMHO.
Any reason to keep the old behavior?

Thanks,
Stefan