keg_relocate: skip running patchelf on bun binaries

[cho-m]

The .bun section needs to occur at a specific location. Upstream does support relocating interpreter (at least via NixOS/patchelf) but either patchelf.rb or RUNPATH relocation results in broken binary.

Was originally going to handle with

• formula: add skip_relocate_dynamic_linkage #22442

As wanted to check if newer bun helped, but looks like relocation doesn't work in 1.4.0 even after

• elf: pick the writable PT_LOAD that contains .bun, not the first one oven-sh/bun#31024
• https://github.com/Homebrew/homebrew-core/actions/runs/32392766548/job/96504251147?pr=299808#step:4:71

Should still be easy to check locally in future if a patchelf.rb upgrade helps by undoing this skip and running brew install bun && brew bottle bun && brew test bun.

Also want to get this in before bun dependents start propagating gzip hack.

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[Copilot]

Pull request overview

This PR adjusts Linux keg relocation so that bottling (placeholder relocation) skips running patchelf on ELF binaries that are known to be corrupted by it (specifically those containing a .bun section), while also renaming the internal relocation keyword to be broader than the previous skip_protodesc_cold flag.

Changes:

• Rename the relocate_dynamic_linkage keyword from skip_protodesc_cold: to with_placeholders: across Keg relocation implementations.
• On Linux, skip RPATH/interpreter relocation (and thus avoid invoking patchelf) for ELF files whose section list includes protodesc_cold or .bun when doing placeholder relocation.
• Update the placeholder-relocation call site to pass the new keyword.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
Library/Homebrew/keg_relocate.rb	Renames the relocation keyword and updates the placeholder-relocation call site.
Library/Homebrew/extend/os/mac/keg_relocate.rb	Keeps macOS override signature in sync with the renamed keyword (no behavioral change).
Library/Homebrew/extend/os/linux/keg_relocate.rb	Adds the .bun-section skip (and refactors the skip flag) to avoid patchelf for affected binaries during bottling.

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[MikeMcQuaid]

Thanks!