Rollup merge of #88289 - durin42:llvm-14-attrs, r=nikic
Rollup merge of #88289 - durin42:llvm-14-attrs, r=nikic

Fixes for LLVM change 0f45c16f2caa7c035e5c3edd40af9e0d51ad6ba7

More details in the individual commit messages, but the summary is: LLVM deleted an unused-to-them method that we used, we worked around it to avoid annoying cleanup/restructuring in the Rust-side code.

graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust