Remove support for HP-UX

[petk]

Correct me if this is wrong but I think this is also kind of already suitable for PHP-8.6:

HP-UX is discontinued system since 2026-01-01:
https://userapps.support.sap.com/sap/support/knowledge/en/3629028

Recent compilers also don't work there anymore.

Changes:

• Non-standard '-threads' flag check removed.
• ZEND_HRTIME_PLATFORM_HPUX preprocessor macro renamed to ZEND_HRTIME_PLATFORM_SUNOS as it is now related to only Solaris/illumos systems.
• Check for HP-UX style reentrant time functions adjusted. This wasn't reproducible on any known system so far.
• LOG_NEWS and LOG_UUCP conditions removed as all Unix-like systems should have them (Windows build have definitions provided in win32/syslog.h).
• Check for <sys/pstat.h> header removed as it is relevant only on HP-UX.
• The .sl file extension for shared PHP extensions is with this also removed, making extension either .so (Unix-like systems), or .dll (Windows).

[bukka]

It seems there is still extended support till 2028 so I don't see that much point to drop it yet.

[petk]

It seems there is still extended support till 2028 so I don't see that much point to drop it yet.

Ok, I'll wait till 2028 with this then. Otherwise, on HP-UX PHP recent versions can't be built anymore.

[NattyNarwhal]

If you're going to remove support for upstream-unsupported platforms, there's a few other ones that are IIRC no longer actually supported I saw just perusing the diff (SCO, IRIX, OSF).

[petk]

If you're going to remove support for upstream-unsupported platforms, there's a few other ones that are IIRC no longer actually supported I saw just perusing the diff (SCO, IRIX, OSF).

If I remember correctly, IRIX has been already removed from the build system, SCO and OSF also. At least in their majorities of checks (there are those posix emulation threads flags still there perhaps). What is left in the C code (if any), I'll for now avoid it. I'm mainly focusing only on the build for now. This should be indeed removed if anything is left. But not in this PR to keep changes simpler to manage.

P.S.: I'll check in more details later, just for the info. That IRIX check for reentrant functions is actually still relevant but it is for Solaris 10 mainly only. Just naming is weird as leftover.