Link std statically in rustc_driver

Author: Zoxc

src/main.rs

@@ -1,3 +1,6 @@
+// We need this feature as it changes `dylib` linking behavior and allows us to link to
+// `rustc_driver`.
+#![feature(rustc_private)]
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 

tests/compile-test.rs

@@ -1,3 +1,6 @@
+// We need this feature as it changes `dylib` linking behavior and allows us to link to
+// `rustc_driver`.
+#![feature(rustc_private)]
 #![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(unused_extern_crates)]