The upstream library rclone uses for rclone mount no longer supports
freebsd. Not only is it broken, but it no longer compiles.
This patch disables rclone mount for freebsd.
However all is not lost for freebsd users - compiling rclone with the
`cmount` tag, so `go install -tags cmount` will install a working
`rclone mount` command which uses cgofuse and the libfuse C library
directly.
Note that the binaries from rclone.org will not have mount support as
we don't have a freebsd build machine in CI and it is very hard to
cross compile cmount.
See: https://github.com/bazil/fuse/issues/280Fixes#5843
The purpose of this is to make it easier to maintain and eventually to
allow the rclone backends to be re-used in other projects without
having to use the rclone configuration system.
The new code layout is documented in CONTRIBUTING.