fixup! Add safety dependency to alloc and std crates

Author: tautschnig

library/alloc/src/lib.rs

@@ -91,6 +91,7 @@
 //
 // Library features:
 // tidy-alphabetical-start
+#![cfg_attr(kani, feature(kani))]
 #![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))]
 #![cfg_attr(not(no_global_oom_handling), feature(const_btree_len))]
 #![feature(alloc_layout_extra)]
@@ -130,7 +131,6 @@
 #![feature(inplace_iteration)]
 #![feature(iter_advance_by)]
 #![feature(iter_next_chunk)]
-#![feature(kani)]
 #![feature(layout_for_ptr)]
 #![feature(local_waker)]
 #![feature(maybe_uninit_slice)]

library/std/src/lib.rs

@@ -269,7 +269,7 @@
 #![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
 #![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
 #![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
-#![feature(kani)]
+#![cfg_attr(kani, feature(kani))]
 //
 // Language features:
 // tidy-alphabetical-start