gcc15 does not recognize `-mavx512pf`

[siddhesh]

Originally reported here:

https://bugzilla.redhat.com/show_bug.cgi?id=2336444

gcc 15 dropped support for Xeon Phi CPUs:

https://gcc.gnu.org/gcc-15/changes.html

because of which the -mav512xpf option in config/knl/make_defs.mk is no longer valid.

[loveshack]

I already sent #844 and #845.

[devinamatthews]

#844 is merged but I will leave this open until the other gcc 15 issues are resolved.

[devinamatthews]

As of #874 and #875 I think gcc15 should work fine.

[tecosaur]

Is there any chance of a new release with this fix dropping in the near future? I've run into this issue while trying to use spaCy.