Fix zombie processes
The underlying patch has been taken from https://github.com/ar-/incron/pull/42/commits/196975d26fd04176a1c877fa3c404efd8103c9c2 (see https://github.com/ar-/incron/pull/42).
Also see https://bugzilla.redhat.com/show_bug.cgi?id=1656939 and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=930526 for further information.
Closes: #930526