Use targeted env vars for overriding compiler/linker args on macOS

[erlend-aasland]

No description provided.

[CAM-Gerlach]

FWIW, this looks good from a docs perspective—ultimately up to the subject matter experts (Ned, etc) of course.

[ned-deily]

I like this approach but, as I've just discovered, Homebrew has just changed the game again by making their tcl-tk formula no longer "keg-only". As noted here, we should re-think this a bit in that light. I'll have some more thoughts on it soon.

[erlend-aasland]

I like this approach but, as I've just discovered, Homebrew has just changed the game again by making their tcl-tk formula no longer "keg-only". As noted here, we should re-think this a bit in that light. I'll have some more thoughts on it soon.

Ouch, it's unfortunate that our build instructions are so dependent on Homebrew distribution specifics. Let's create a separate issue for this (unless you already did so).

[erlend-aasland]

As noted python/cpython#102186 (comment), we should re-think this a bit in that light. I'll have some more thoughts on it soon.

I've marked this as a draft until the above has landed.

[erlend-aasland]

I like this approach but, as I've just discovered, Homebrew has just changed the game again by making their tcl-tk formula no longer "keg-only". As noted here, we should re-think this a bit in that light. I'll have some more thoughts on it soon.

@ned-deily, have you had the chance to think about this issue? IMO, it is unfortunate that we rely on Homebrew specifics. Perhaps the best thing to do, is to update the devguide recommendations for how to install the dependencies:

$ brew install pkg-config openssl@1.1 xz gdbm tcl-tk
$ brew link tcl-tk  # <= may produce a warning if already linked

We can then carry on with this PR (and also update the devguide build steps again).

[ned-deily]

@ned-deily, have you had the chance to think about this issue? IMO, it is unfortunate that we rely on Homebrew specifics. Perhaps the best thing to do, is to update the devguide recommendations for how to install the dependencies:

That could be an option. There are a number of other side issues with some of the other dependencies, like which ones should we use from the operating system, and there are the Homebrew differences between Intel and Apple Silicon installations. Alas, I am away right now but will get back to this in a couple of weeks. If you think there is a need to update the guide sooner, we can always tweak it again later.

[erlend-aasland]

No, there's no hurry 🙂 If you're coming to SLC, we can discuss it there. If not, let's pick it up when you're ready.

[erlend-aasland]

@ned-deily, let's land this. We can handle the OpenSSL version in a follow-up PR (python/cpython#99079 (comment))

[ned-deily]

LGTM, thanks!