[new port] math/libpgmath: Compiler-callable math intrinsics library

[jmd]

Summary

This add libpgmath. It is the math library of the flang compiler with support for vector operations.

Patches were in large part adapted from the OpenBSD port.

Test Plan

portlint -Aac clean
poudriere tested HEAD amd64
Older releases lack support of cpuid bits needed.

[jmd]

Add check for older than 12.0

[mat]

Could you use devel/arcanist, or at least generate a diff with full context like it does, with svn diff -x -U9999 or git diff -U9999.

math/libpgmath/Makefile

15 ↗

(On Diff #47675)

1. "for now" everything in the ports tree is true at the time it is committed, so remove it.
2. "only builds" is what ONLY_FOR_ARCHS means, so, remove it.
3. ONLY_FOR_ARCHS_REASONS_<arch> is used when <arch> is not in the supported architectures, so this one will never be used, you should remove the _amd64 bit.

37–41 ↗

(On Diff #47675)

Could possibly be replaced with

IGNORE_FreeBSD_10= blah
IGNORE_FreeBSD_11= blah

math/libpgmath/pkg-descr

1 ↗

(On Diff #47675)

Please provide a longer description, at least one paragraph with two lines.

[jmd]

Comments addressed

[jmd]

Address review comments.

[zeising]

Approved