Add wait-for-seconds feature to pwait(1)
The review of #12676 reminded me that there's a need to wait for a process to exit, but with a limit on how long it should take.
There are some design decisions that need to be made before this can be built:
- CLI flag (
- Appropriate exit value to indicate "process timed out"?
- Single-PID is trivial, and likely to the be the common case, but how does a combination of multiple PIDs AND a timeout value work?
- Related to multiple-PIDs, how verbose should the output be if -v is used? Should there be a -V (more verbose)?