Fix std_detect not being an unstable crate

More fallout from rust-lang#1486

Author: Amanieu

crates/core_arch/src/lib.rs

@@ -35,7 +35,7 @@
     inline_const,
     generic_arg_infer
 )]
-#![cfg_attr(test, feature(test, abi_vectorcall))]
+#![cfg_attr(test, feature(test, abi_vectorcall, stdarch_internal))]
 #![deny(clippy::missing_inline_in_public_items)]
 #![allow(
     clippy::identity_op,

crates/std_detect/src/lib.rs

@@ -13,7 +13,7 @@
 //! * `powerpc64`: [`is_powerpc64_feature_detected`]
 //! * `loongarch`: [`is_loongarch_feature_detected`]
 
-#![stable(feature = "stdsimd", since = "1.27.0")]
+#![unstable(feature = "stdarch_internal", issue = "none")]
 #![feature(staged_api, doc_cfg, allow_internal_unstable)]
 #![deny(rust_2018_idioms)]
 #![allow(clippy::shadow_reuse)]
@@ -42,5 +42,5 @@ extern crate std;
 extern crate alloc;
 
 #[doc(hidden)]
-#[stable(feature = "stdsimd", since = "1.27.0")]
+#[unstable(feature = "stdarch_internal", issue = "none")]
 pub mod detect;

crates/std_detect/tests/macro_trailing_commas.rs

@@ -1,3 +1,5 @@
+#![allow(internal_features)]
+#![feature(stdarch_internal)]
 #![cfg_attr(target_arch = "arm", feature(stdarch_arm_feature_detection))]
 #![cfg_attr(target_arch = "powerpc", feature(stdarch_powerpc_feature_detection))]
 #![cfg_attr(target_arch = "powerpc64", feature(stdarch_powerpc_feature_detection))]

crates/std_detect/tests/x86-specific.rs

@@ -1,4 +1,6 @@
 #![cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+#![allow(internal_features)]
+#![feature(stdarch_internal)]
 
 extern crate cupid;
 #[macro_use]