CI: Use lld for linking LLVM in the x86_64-gnu-debug image.
CI: Use lld for linking LLVM in the x86_64-gnu-debug image.

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