Auto merge of rust-lang#106075 - nbdd0121:ffi-unwind, r=joshtriplett

Partial stabilisation of `c_unwind`

The stabilisation report is at rust-lang#74990 (comment)

cc `@rust-lang/wg-ffi-unwind`

Author: bors

panic_unwind/src/emcc.rs

@@ -47,7 +47,7 @@ static EXCEPTION_TYPE_INFO: TypeInfo = TypeInfo {
     name: b"rust_panic\0".as_ptr(),
 };
 
-// NOTE(nbdd0121): The `canary` field will be part of stable ABI after `c_unwind` stabilization.
+// NOTE(nbdd0121): The `canary` field is part of stable ABI.
 #[repr(C)]
 struct Exception {
     // See `gcc.rs` on why this is present. We already have a static here so just use it.

panic_unwind/src/gcc.rs

@@ -48,8 +48,8 @@ use unwind as uw;
 static CANARY: u8 = 0;
 
 // NOTE(nbdd0121)
-// Once `c_unwind` feature is stabilized, there will be ABI stability requirement
-// on this struct. The first two field must be `_Unwind_Exception` and `canary`,
+// There is an ABI stability requirement on this struct.
+// The first two field must be `_Unwind_Exception` and `canary`,
 // as it may be accessed by a different version of the std with a different compiler.
 #[repr(C)]
 struct Exception {

panic_unwind/src/seh.rs

@@ -52,7 +52,7 @@ use core::mem::{self, ManuallyDrop};
 use core::ptr;
 use libc::{c_int, c_uint, c_void};
 
-// NOTE(nbdd0121): The `canary` field will be part of stable ABI after `c_unwind` stabilization.
+// NOTE(nbdd0121): The `canary` field is part of stable ABI.
 #[repr(C)]
 struct Exception {
     // See `gcc.rs` on why this is present. We already have a static here so just use it.