python314-freethreading: fix build on macOS >=10.7 and =<10.11

[aeiouaeiouaeiouaeiouaeiouaeiou]

Review and ideas are needed.
I don't have access to systems running macOS 10.6 and 10.11, but according to @barracuda156 SL requires legacysupport for arc4random_buf().

Tested on

macOS 10.8.5 12F2560 x86_64
Xcode 5.1.1 5B1008

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• checked your Portfile with port lint?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?

[macportsbot]

Notifying maintainers:
@jmroot for port python314.

[barracuda156]

@aeiouaeiouaeiouaeiouaeiouaeiou Well, py*-freethreading definitely build on 10.6 from my ports. You can see there how to fix the logic in the portfile.
I did not try on 10.5, can do that, if you are curious.

What is still broken:

1. Universal which includes ppc (existing implementation never worked). I had fixed it earlier when I was building universal on 10.5, but that fix is not committed (so it is still broken in my fork as well).
2. LTO variants are broken for 3.12+. Since 3.11 +lto works, should be fixable.

Probably you could avoid legacysupport by implementing whatever needed by hand, but legacy-support is a 0 dependency port, should not pose a problem. (Besides convincing someone to merge a fix…)

[barracuda156]

@aeiouaeiouaeiouaeiouaeiouaeiou LTO for gcc was broken by:
python/cpython@8482ce4 (ironically, given commit title)
python/cpython@5b070c0 (this was what broke 3.12+)

[barracuda156]

@aeiouaeiouaeiouaeiouaeiouaeiou Everything builds on 10.5 too, freethreading and lto now:

[aeiouaeiouaeiouaeiouaeiouaeiou]

@barracuda156 I will update this PR next week while I am recovering in the hospital after surgery.

[barracuda156]

@aeiouaeiouaeiouaeiouaeiouaeiou Get well!