ci: Use clang-18

[maflcko]

Use clang-18, which comes with bugfixes and sanitizer upgrades.

[DrahtBot]

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ACK	fanquake

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #29165 (build: Bump clang minimum supported version to 15 by maflcko)
• #28710 (Remove the legacy wallet and BDB dependency by achow101)
• #28687 (C++20 std::views::reverse by stickies-v)
• #25972 (build: no-longer disable WARN_CXXFLAGS when CXXFLAGS is set by fanquake)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[fanquake]

I don't think Mac cross should change until depends and guix does?

[maflcko]

Oh I forgot that the pre-built binary has the distro assumed:

bitcoin/depends/packages/native_llvm.mk

Line 9 in 4373414

$(package)_file_name=clang+llvm-$($(package)_version)-x86_64-linux-gnu-ubuntu-22.04.tar.xz

Maybe a comment can be added that the two must match.

[fanquake]

has the distro assumed:
Maybe a comment can be added that the two must match.

They don't necessarily have to, i.e, the "Ubuntu" bins will build macOS binaries on Fedora, or Alpine, for example. Or are you only talking about the version?

[fanquake]

ACK fa75220