Enable the rust_2024_compatibility lint

Enable this lint with the expectation that we will eventually be
upgrading editions. There are some exceptions needed, and
`unsafe_op_in_unsafe_fn` will take a while to go through.

(backport <#4585>)
(cherry picked from commit 2fe8b17)

Author: tgross35

src/lib.rs

@@ -10,6 +10,15 @@
     unused_macros,
     unused_macro_rules,
 )]
+// Prepare for a future upgrade
+#![warn(rust_2024_compatibility)]
+// Things missing for 2024 that are blocked on MSRV or breakage
+#![allow(
+    missing_unsafe_on_extern,
+    edition_2024_expr_fragment_specifier,
+    // Allowed globally, the warning is enabled in individual modules as we work through them
+    unsafe_op_in_unsafe_fn
+)]
 #![cfg_attr(libc_deny_warnings, deny(warnings))]
 // Attributes needed when building as part of the standard library
 #![cfg_attr(feature = "rustc-dep-of-std", feature(link_cfg, no_core))]