Shipping llvm-strip w/ a symlink breaks when bootstrap compiler doesn't contain any LLVM tools

[jieyouxu]

This breaks bootstrapping when the bootstrap compiler doesn't contain any LLVM tools as is the case when cg_clif bootstraps rustc:

Building stage0 tool lld-wrapper (x86_64-unknown-linux-gnu)
     Compiling lld-wrapper v0.1.0 (/home/runner/work/rustc_codegen_cranelift/rustc_codegen_cranelift/rust/src/tools/lld-wrapper)
      Finished `release` profile [optimized] target(s) in 0.43s
  thread 'main' panicked at src/lib.rs:1714:24:
src.symlink_metadata() failed with No such file or directory (os error 2) ("src = /home/runner/work/rustc_codegen_cranelift/rustc_codegen_cranelift/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-objcopy")

It should probably check builder.config.llvm_enabled(target_compiler.host) && builder.config.llvm_tools_enabled before copying to ensure that llvm-objcopy exists in the first place.

Originally posted by @bjorn3 in #131405 (comment)

[bjorn3]

Worked around this in rust-lang/rustc_codegen_cranelift@b5966e4e.

[jieyouxu]

PR: #132720

[hoodmane]

I'm also hitting this. Can confirm that #132720 fixes the problem.