Use Rust ABI for __rust_start_panic and _{rdl,rg}_oom

library/alloc/src/alloc.rs

@@ -398,13 +398,13 @@ pub mod __alloc_error_handler {
 
     // if there is no `#[alloc_error_handler]`
     #[rustc_std_internal_symbol]
-    pub unsafe extern "C-unwind" fn __rdl_oom(size: usize, _align: usize) -> ! {
+    pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
         panic!("memory allocation of {size} bytes failed")
     }
 
     // if there is an `#[alloc_error_handler]`
     #[rustc_std_internal_symbol]
-    pub unsafe extern "C-unwind" fn __rg_oom(size: usize, align: usize) -> ! {
+    pub unsafe fn __rg_oom(size: usize, align: usize) -> ! {
         let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
         extern "Rust" {
             #[lang = "oom"]

library/panic_abort/src/lib.rs

@@ -30,7 +30,7 @@ pub unsafe extern "C" fn __rust_panic_cleanup(_: *mut u8) -> *mut (dyn Any + Sen
 
 // "Leak" the payload and shim to the relevant abort on the platform in question.
 #[rustc_std_internal_symbol]
-pub unsafe extern "C-unwind" fn __rust_start_panic(_payload: *mut &mut dyn BoxMeUp) -> u32 {
+pub unsafe fn __rust_start_panic(_payload: *mut &mut dyn BoxMeUp) -> u32 {
     // Android has the ability to attach a message as part of the abort.
     #[cfg(target_os = "android")]
     android::android_set_abort_message(_payload);

library/panic_unwind/src/lib.rs

@@ -104,7 +104,7 @@ pub unsafe extern "C" fn __rust_panic_cleanup(payload: *mut u8) -> *mut (dyn Any
 // Entry point for raising an exception, just delegates to the platform-specific
 // implementation.
 #[rustc_std_internal_symbol]
-pub unsafe extern "C-unwind" fn __rust_start_panic(payload: *mut &mut dyn BoxMeUp) -> u32 {
+pub unsafe fn __rust_start_panic(payload: *mut &mut dyn BoxMeUp) -> u32 {
     let payload = Box::from_raw((*payload).take_box());
 
     imp::panic(payload)

library/std/src/panicking.rs

@@ -47,7 +47,7 @@ extern "C" {
 }
 
 #[allow(improper_ctypes)]
-extern "C-unwind" {
+extern "Rust" {
     /// `payload` is passed through another layer of raw pointers as `&mut dyn Trait` is not
     /// FFI-safe. `BoxMeUp` lazily performs allocation only when needed (this avoids allocations
     /// when using the "abort" panic runtime).