Fixes #10551 Search for LLVM 17 during initial setup

[KilianB]

What does this PR do?

• Update build script to not failed if LLVM - 17 isn't found.
• Docs are updated to point for contributors

Fixes #10551

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)
• [x ] Code changes

How did you verify your code works?

After changes build succeedes locally. Beforehand it did not.

[TiBianMod]

@paperdave made this changes before 2-3 days on this PR #10492

[KilianB]

In that case the build.sh was missed. :-)

- CC=${CC:-$(which clang-17 || which clang || which cc)}
+ CC=${CC:-$(which clang-16 || which clang || which cc)}
- CXX=${CXX:-$(which clang++-17 || which clang++ || which c++)}
+ CXX=${CXX:-$(which clang++-16 || which clang++ || which c++)}

[paperclover]

ah, i missed setup.sh

we should use the version of LLVM set in the variable lol

[paperclover]

can you switch it all to LLVM 16. we recently did an upgrade but had issues so we downgraded. the setup.sh is the one that was missed during the downgrade

[KilianB]

@paperdave done. There were some additional changes in env.sh that might have been missed as well. In the commit Jarred also added CMAKE flags.

I am not well versed of the impact of those, should all these changes in the file be reverted?

https://github.com/oven-sh/bun/pull/10161/files#diff-5a4957bc7903de70fcfb50dc6aa8851f9d16d84566568736af52e9e2df8c8628

[paperclover]

no, i think those flags fixed a linux crash