[nll] librustc_llvm: enable feature(nll) for bootstrap

Author: memoryruins

src/librustc_llvm/lib.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![cfg_attr(not(stage0), feature(nll))]
 #![feature(static_nobundle)]
 
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",