David Thompson authored May 08, 2019 and Romain Bouvier committed May 08, 2019

- The PATH "/bin:/usr/bin" may not be a valid search path on the user's
machine.  The screen locking program may be in /usr/local/bin or
elsewhere.  Distros that do not conform to the FHS, such as GuixSD and
NixOS, will not have their executables in either location.  Thus, we
simply leave PATH alone.
- OpenBSD and FreeBSD also patch xflock4 to add their own PATH...
- Fix bug #12282