Remove unused HOMEBREW_ARCHFLAGS

[cho-m]

Unused since d733512

---

• Have you followed our Contributing guidelines?
• Have you checked for other open Pull Requests for the same change?
• Have you explained what your changes do? Performance claims (e.g. "this is faster") must include Hyperfine benchmarks.
• Have you explained why you'd like these changes included, not just what they do?
• For bug fixes, have you given step-by-step brew commands to reproduce the bug?
• Have you written new tests (excluding integration tests)? Here's an example.
• Have you successfully run brew lgtm (style, typechecking and tests) locally?

---

• AI was used to generate or assist with generating this PR.

---

[Copilot]

Pull request overview

This PR removes HOMEBREW_ARCHFLAGS plumbing from the “super” build environment, reflecting that it is no longer consumed by the super/cc shim and avoiding exporting an unused build variable.

Changes:

• Stop exporting HOMEBREW_ARCHFLAGS from the super build environment setup.
• Remove parsing/exposing of HOMEBREW_ARCHFLAGS in the super/cc shim and stop appending it to compiler flags.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Library/Homebrew/shims/super/cc	Removes archflags reader/init and stops appending it to computed cflags.
Library/Homebrew/extend/ENV/super.rb	Stops setting HOMEBREW_ARCHFLAGS in setup_build_environment.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[MikeMcQuaid]

Nice, thanks!