Do not capture stderr in the compiler. Instead just panic silently for fatal errors

src/libsyntax/lib.rs

@@ -54,7 +54,7 @@ macro_rules! panictry {
             Ok(e) => e,
             Err(mut e) => {
                 e.emit();
-                panic!(FatalError);
+                FatalError.raise()
             }
         }
     })