This reapplies 66f7540, which adds supports for hardlinks/junctions on
Windows systems where developer mode is not enabled.
The commit was reverted on account of multiple issues:
* Checks added to prevent dangling symlinks were interfering with
existing CI builds on Linux (i.e. builds that otherwise succeed were
failing for creating dangling symlinks).
* The logic also updated symlinking to perform redirection of relative
paths, which lead to malformed symlinks.
This commit fixes these issues.
349ba83bc6