Auto merge of #77565 - khyperia:codegen-backend-dep, r=ecstatic-morse
Auto merge of #77565 - khyperia:codegen-backend-dep, r=ecstatic-morse

Add -Z codegen-backend dylib to deps

When the codegen-backend dylib changes, the program should be rebuilt.

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Unfortunately I was unable to test this works locally due to running into a TLS issue when running the custom backend, `thread 'rustc' panicked at 'no ImplicitCtxt stored in tls', compiler/rustc_middle/src/ty/context.rs:1750:54`, which seems similar to https://github.com/rust-lang/rust/issues/62717 but has a completely different cause and backtrace.

`@eddyb` said to ping `@Mark-Simulacrum` about what they think about this, so, ping!

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