update gcc codegen to match new write_bytes signature

Author: the8472

compiler/rustc_codegen_gcc/example/mini_core.rs

@@ -677,7 +677,7 @@ pub mod intrinsics {
     #[rustc_intrinsic]
     pub fn bswap<T>(x: T) -> T;
     #[rustc_intrinsic]
-    pub unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
+    pub unsafe fn write_bytes<T, B>(dst: *mut T, val: B, count: usize);
     #[rustc_intrinsic]
     pub unsafe fn unreachable() -> !;
 }

compiler/rustc_codegen_gcc/example/mini_core_hello_world.rs

@@ -127,7 +127,7 @@ impl<T: ?Sized, U: ?Sized> CoerceUnsized<Unique<U>> for Unique<T> where T: Unsiz
 
 unsafe fn zeroed<T>() -> T {
     let mut uninit = MaybeUninit { uninit: () };
-    intrinsics::write_bytes(&mut uninit.value.value as *mut T, 0, 1);
+    intrinsics::write_bytes(&mut uninit.value.value as *mut T, 0u8, 1);
     uninit.value.value
 }