Some improvement on the deps building

[illwieckz]

• Do not cross-compile pkgconfig, it is part of the cross-compilation toolchain;
• Reword a comment because we don't build SDL with pkg-config anymore;
• Rework the macos-amd64 setup a bit;
• Do not build OpenAL utils.

Extracted from:

• WIP: example of implementing external deps for extra platforms #1823

[slipher]

This looks wrong. I've never managed to find any documentation for autotools platform strings, but for me the autodetection reports darwin24.6.0 for the last component. This tracks "Kernel version" in the system's about screen.

[illwieckz]

Well, actually we may just be able to use x86_64-apple-darwin without version, what we need for the version is the deployment target. That last keyword seems to be mostly random when I look around on the net: darwin<VERSION>, macosx<VERSION>, macos<VERSION>…

[illwieckz]

There is explicit code for those three syntaxes in LLVM:

• Matching darwin* and macos*:

  • https://github.com/llvm/llvm-project/blob/5dd2b06d60d3eb9b07c7513358ad8b04386f79bc/llvm/lib/TargetParser/Triple.cpp#L702
  • https://github.com/llvm/llvm-project/blob/5dd2b06d60d3eb9b07c7513358ad8b04386f79bc/llvm/lib/TargetParser/Triple.cpp#L710

• Parsing Darwin and macOS versions:

  • https://github.com/llvm/llvm-project/blob/5dd2b06d60d3eb9b07c7513358ad8b04386f79bc/llvm/lib/TargetParser/Triple.cpp#L1474-L1499

We can put either Darwin version or macOS version, and in fact it's better for us to use the macOS version since we already know it and then we don't have to search for the related Darwin version.

[illwieckz]

I modified the string from macosx<VERSION> to macos<VERSION> because we're in the future.

[illwieckz]

I forgot to say it's not an autotools thing, but a compiler thing, autotools is very likely just reporting the output of cc -dumpmachine when we let it guess.

[slipher]

That looks OK then, LGTM.

Autotools does parse the strings in the config.sub script. It rejects some parts if they don't match any pattern and replaces some strings with others.