Set SA_ONSTACK in zend_sigaction

[dunglas]

I'm currently working on a new SAPI for web servers written in Go.

Many virtual machines, including Go VM, depend on signals using SA_ONSTACK . This flag allows a thread to define a new alternate signal stack. Many argue that SA_ONSTACK should be a default, but it's not the case (yet).

This patch sets the SA_ONSTACK flag when PHP calls sigaction().

Python merged a similar patch (python/cpython#24730) in 2021 (Python 3.10+) for the same reasons, with no issues.

[Girgias]

Shouldn't this target 8.2? master is currently 8.3-dev

[dunglas]

@Girgias, @krakjoe said on internals

Master should be targeted, no RFC is required, and the patch looks fine to me.

Your call :)

[devnexen]

I definitely would like to see it at least for 8.3, @dunglas is doing the right things IMHO nor I have any problem seeing also into the 8.2 branch but should not we ask one of the release managers opinion just to be safe or is it ok ?

[iluuu1994]

LGTM. I think master should be fine, unless the RMs think this should target an earlier branch.

[Girgias]

@saundefined @adoy opinions about landing this in 8.2 or should this be deferred to 8.3?

[adoy]

Unless there is a very strong need to have this change in 8.2 I would recommend to target 8.3 since we already are in an RC phase.