Linker error when building rustc after LLVM version change

[RalfJung]

I just got this build error after rebasing over rustc master:

$ nice ./x.py test src/test/ui --test-args ub-wide --bless
Building rustbuild
    Finished dev [unoptimized] target(s) in 0.15s
Building stage0 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized + debuginfo] target(s) in 0.14s
Copying stage0 std from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Building stage0 compiler artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
    Finished release [optimized + debuginfo] target(s) in 0.27s
Copying stage0 rustc from stage0 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu / x86_64-unknown-linux-gnu)
Assembling stage1 compiler (x86_64-unknown-linux-gnu)
Building stage1 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
error: process didn't exit successfully: `/home/r/src/rust/rustc.2/build/bootstrap/debug/rustc -vV` (exit status: 127)
--- stderr
/home/r/src/rust/rustc.2/build/x86_64-unknown-linux-gnu/stage1/bin/rustc: error while loading shared libraries: libLLVM-14-rust-1.63.0-nightly.so: cannot open shared object file: No such file or directory

Build completed unsuccessfully in 0:00:00

That file exists in ./build/x86_64-unknown-linux-gnu/ci-llvm/lib/libLLVM-14-rust-1.63.0-nightly.so but not anywhere else.

@jyn514 thinks this is probably because the rustc_llvm build scripts fails to run after the version change.

[ehuss]

Posted #98513 with a (hacky) fix.