rust-std component filled with unnecessary rlibs

[retep998]

I'm pretty sure over half the rlibs in this list are completely useless. Normal crates would only need libstd and its dependencies, while plugins don't use rlibs at all.

[Mark-Simulacrum]

@alexcrichton We can certainly remove these rlibs, but I think they are necessary for something -- maybe regular crates with extern crate rustc_serialize; or something like that?

[alexcrichton]

These are needed for plugins, when you extern crate proc_macro it needs to transitively load all of that crate's dependencies, even if they're rlibs. In this case that pulls in some crates.io rlibs.

Everything that's not transitively a dependency of proc_macro is then still required for unstable plugins, so closing.

[retep998]

But proc_macro is only available as a dylib, not an rlib, which means transitive dependencies are being linked in as dylibs too, which means those rlibs definitely are not needed for proc_macro! Ditto for plugins, they pull in everything as dylibs, not rlibs!