* Compare mount output using base of dirname
If you're building from a bind-mounted directory, the build will
fail as it will find two entries to unmount, but a single unmount
will remove them both causing an error. Adding a space means that
the mountpoint will only match with a single mount entry ; the
expected path, rather than the pre bind-mount.
* Switch to awk instead of mount, grep, cut pipes
Retry unmount 5 times and give up, letting the user know that they need to resolve the issue manually
---------
Co-authored-by: David Peverley <pev@analogue-micro.com>
Co-authored-by: Serge Schneider <serge@raspberrypi.com>
