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python-build-standalone has exploded in popularity, with over 70M downloads all-time. But what is a "standalone" Python build? It wasn't obvious to me at first! Initially, I didn't understand what problem was being solved or why it mattered...

First, some context on the problem. Normally, when you build CPython on Linux or macOS, several system paths are hardcoded into the binary.

This is fine if you're building and installing Python on a single machine... but it's a problem if you want to pre-build Python and then distribute it to other machines, since those paths might be wrong!

Which reminds me of my main problem with standalone builds on macOS: I can’t compile wheels because they assume some super weird Xcode path. I think it’s fair to say they can’t go full mainstream with that limitation so I wonder if that’s solvable at all? :-/

What’s this? I don’t have this problem and I build wheels all the time. Is there an issue somewhere?

yes, mortals like myself have Xcode at /Applications/Xcode.app but standalone expects it at /Applications/Xcode_15.2.app "Compiling with an SDK that doesn't seem to exist: /Applications/Xcode_15.2.app/..." Here's the example I could come up with fastest.

yeah, mostly to add Homebrew stuff to -I and -L

Okay great. I have a fix for this.

I figured out what's going on. CPython itself strips these flags _unless_ CFLAGS is set as an environment variable. github.com/indygreg/pyt...