Patch libstd arg initialization for rust#66547

[bjorn3]

Once rust-lang/rust#66547 lands, the linux-gnu target will use #[link_section] to initialize the list of arguments. Because cranelift-module doesn't provide an api to place functions and statics in a specific section, we will need to patch libstd to revert the rust PR.

[joshtriplett]

This seems unfortunate. Is there any plan to support writing things to different sections in the cranelift backend?

[bjorn3]

object does support this, so by modifying cranelift-object it should be possible to implement it. faerie however only has support for custom sections to which nobody refers to. For cranelift-simplejit it wouldn't even make sense to support this, as no object files are emitted. The SimpleJIT backend currently supports passing arguments to the jitted code, however when linking to libstd, we load the dylib for it. By using .init_array, the loaded libstd will get initialized with the arguments of the rustc process itself, instead of the content of the JIT_ARGS env var, which cg_clif passes to the generated main shim.

I think it would be the best if the args passed to main would be used whenever possible. It could for example override the args set by .init_array.

[bjorn3]

Patched in bjorn3@b97df0b.