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

Author: memoryruins

src/librustc_codegen_utils/lib.rs

@@ -19,6 +19,7 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(custom_attribute)]
+#![cfg_attr(not(stage0), feature(nll))]
 #![allow(unused_attributes)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]