A directory and a symlink to it under the same relative path in a
different prefix
```
/prefix1/dir/
/prefix1/dir/file
/prefix2/dir -> /prefix1/dir/
```
are not a blocker to create a view. The view structure simply looks like
this:
```
/view/dir/
/view/dir/file
```
This should be the case independently of the order in which we visit
prefixes, so we could in principle create views order independently.
e4a8d45d86