On Windows, passing "*" as mountPoint to the mount/mount RC command
auto-assigns a drive letter (e.g. "Z:"), but the resolved letter was
never propagated back to mountlib. This caused liveMounts to be keyed
on the literal "*", breaking tracking of multiple mounts and making
unmount unreliable.
Change MountFn to return the actual mount point as an additional
return value. Update MountPoint.Mount() to store the resolved value,
and mountRc() to use it as the liveMounts key. The mount/mount RC
response now returns the actual mountPoint so callers can discover
which drive letter was assigned.
Summary:
In cases where cmount is not available in macOS, we alias nfsmount to mount command and transparently start the NFS server and mount it to the target dir.
The NFS server is started on localhost on a random port so it is reasonably secure.
Test Plan:
```
go run rclone.go mount --http-url https://beta.rclone.org :http: nfs-test
```
Added mount tests:
```
go test ./cmd/nfsmount
```
The tests are now run for the mount commands and for the plain VFS.
This makes the tests much easier to debug when running with a VFS than
through a mount.
Nick Craig-Wood
overallteachandNick Craig-Wood
Saleh DindarandNick Craig-Wood