pgrep: should show an error message if pattern is longer than 15 chars and there's no match about procps

[cakebaker]

Hm, it looks like this error only shows up if there is no match. If there is a match, there is no such error message:

$ pgrep pool_workqueue_release
3

So this means an extra flag doesn't make much sense.

It's a low-prio bug. I'm not sure whether we should fix it in our code or adapt the procps test suite accordingly when we run their test suite against our code.

[Krysztal112233]

Does this need to be made compatible with GNU as well? Maybe it would be better to set an extra flag (such as --extended-pattern) as an extension of the uutils implementation?