Implement Copy and Clone manually for BuddyEntry.

This fixes a warning that may in the future become an error, about the
possibility for unaligned references, since the derive macros apparently
rely on creating references to fields. Unaligned references are direct
UB.

src/allocator/frame/buddy.rs

@@ -16,7 +16,6 @@ use crate::{
 #[repr(transparent)]
 struct BuddyUsage(u8);
 
-#[derive(Clone, Copy)]
 #[repr(packed)]
 struct BuddyEntry<A> {
     base: PhysicalAddress,
@@ -28,6 +27,19 @@ struct BuddyEntry<A> {
     phantom: PhantomData<A>,
 }
 
+impl<A> Clone for BuddyEntry<A> {
+    fn clone(&self) -> Self {
+        Self {
+            base: self.base,
+            size: self.size,
+            skip: self.skip,
+            used: self.used,
+            phantom: PhantomData,
+        }
+    }
+}
+impl<A> Copy for BuddyEntry<A> {}
+
 impl<A: Arch> BuddyEntry<A> {
     fn empty() -> Self {
         Self {