Draft: Add -ld_classic linker option to mac builds

[d-led]

Problem

linking both Pony programs and ponyc fail with ld: Missing -platform_version option

Discussion

see #4454

ld versions

@d-led:

ld -v
@(#)PROGRAM:ld  PROJECT:dyld-1015.7
BUILD 18:48:43 Aug 22 2023
configured to support archs: armv6 armv7 armv7s arm64 arm64e arm64_32 i386 x86_64 x86_64h armv6m armv7k armv7m armv7em
will use ld-classic for: armv6 armv7 armv7s arm64_32 i386 armv6m armv7k armv7m armv7em
LTO support using: LLVM version 15.0.0 (static support for 29, runtime is 29)
TAPI support using: Apple TAPI version 15.0.0 (tapi-1500.0.12.3)

[SeanTAllen]

You can remove the cmakelist change

[SeanTAllen]

Can you convert this to a draft PR so that merge isn't an option for now?

[d-led]

reverted the cmake change & converted to draft. PS I chedked "Allow edits by maintainers", in case you want to commit directly to the branch

[SeanTAllen]

@d-led awesome. thanks. if this works, do you want to write the release notes and "bring this all the way home" or would you prefer for me to step in for "the extras" like release notes?

[SeanTAllen]

@d-led which version of xcode introduced this problem?

[SeanTAllen]

This doesn't work with the older xcode. Sadly.

[d-led]

This doesn't work with the older xcode. Sadly.

as expected. Version check or an optional flag in both cmake and ponyc?

[d-led]

@d-led which version of xcode introduced this problem?

I haven't yet followed up and thus don't know ☹️ . I would suggest decoupling the work-around from the xcode versions: who knows, maybe they'll invert the default...

[SeanTAllen]

the problem with version check is it would have to be done at the time linking is done. it doesnt do any good for something that is distributing binaries like us, homebrew etc if it isn't done at the time each pony program is being linked.

[d-led]

collecting some refences:

• compilation fails with unknown option : -platform_version fstpackage/fst#238
• not to compile ios app with adobe animate airsdk/Adobe-Runtime-Support#2866
• [LLVM on Mojave] ld: unknown option: -platform_version Homebrew/homebrew-core#52461
• https://bugs.llvm.org/show_bug.cgi?id=44813
• https://reviews.llvm.org/D74784

[d-led]

it seems, xcode 15 is the culprit (unverified)

[SeanTAllen]

Closed "in favor of" #4466 if we can get it validated.