Add pcntl to (non-mandatory) requirements

[schmunk42]

What steps will reproduce the problem?

Running into weird problem with yii2-queue, eg. non-terminating child-processes, etc..

What is the expected result?

"Correct", unix-style process handling.

What do you get instead?

Weird errors :)

Additional info

Related:

• Refine docs for retryable, TTR and attempts yii2-queue#229
• Queue just stop executing job and therefore (MySQL server has gone away) yii2-queue#439

Q	A
Yii version	2.0.?
PHP version	8.x
Operating system	Docker Debian

I think it should be checked for pcntl in RequirementsChecker and I'd also recommend to add this to the minimal Docker images.

[samdark]

Yes, I think it is a good idea to add it to requirements checker as optional dependency.

[samdark]

Do you have some time for a pull request?

[schmunk42]

Should be fixed in #19780.