legacy code), if the builtin service forks (not all do), avoid leaking
listening sockets into the child process.
If the child process were to keep copies of the listening sockets
around and then hang about for a long time, it would prevent inetd
from being able to re-bind them upon restart.
The listening sockets are tagged close-on-exec, but that doesn't help
when one doesn't exec.
Patch from my own very old PR 8253.
e62b84ba61