Revert changes to lib.rs

Author: jackpot51

src/lib.rs

@@ -15,11 +15,11 @@
 #![crate_name = "libc"]
 #![crate_type = "rlib"]
 #![cfg_attr(not(feature = "rustc-dep-of-std"), deny(warnings))]
-#![allow(bad_style, overflowing_literals, improper_ctypes, unknown_lints, unused_attributes)]
+#![allow(bad_style, overflowing_literals, improper_ctypes, unknown_lints)]
 // Attributes needed when building as part of the standard library
 #![cfg_attr(
     feature = "rustc-dep-of-std",
-    feature(link_cfg, no_core)
+    feature(cfg_target_vendor, link_cfg, no_core)
 )]
 // Enable extra lints:
 #![cfg_attr(feature = "extra_traits", deny(missing_debug_implementations))]