relibc: fix edition-2024 unsafe-op-in-unsafe-fn in epoll::convert_event

Commit dd2cd443 introduced unsafe fn convert_event(*const Event,
*mut epoll_event) but dereferenced both pointers without unsafe
blocks. Edition 2024 (relibc's top-level Cargo.toml) enforces
unsafe-op-in-unsafe-fn by default with -D, so this caused rustc
E0133 errors during canonical build:

  error[E0133]: dereference of raw pointer is unsafe and requires
  unsafe block
    --> src/platform/redox/epoll.rs:139:17 / 143:5

The fix wraps each deref in an explicit unsafe { } block with a
SAFETY justification, keeping the outer unsafe fn signature so the
validity proof stays on callers (the rest of epoll.rs already
upholds those invariants).

No semantic change — same machine code after the wrap, just edition
2024-compliant source.

src/platform/redox/epoll.rs

@@ -136,17 +136,23 @@ impl PalEpoll for Sys {
 }
 
 unsafe fn convert_event(event_ptr: *const Event, target_ptr: *mut epoll_event) -> bool {
-    let event = *event_ptr;
+    // SAFETY: callers guarantee both pointers are valid, properly aligned,
+    // and point to initialized storage. The unsafe blocks satisfy edition
+    // 2024's `unsafe-op-in-unsafe-fn` rule (rustc E0133); the function
+    // signature stays `unsafe fn` to push the validity proof onto callers.
+    let event = unsafe { *event_ptr };
     if event.id == syscall::EVENT_TIMEOUT_ID {
         return false;
     }
-    *target_ptr = epoll_event {
-        events: event_flags_to_epoll(event.flags),
-        data: epoll_data {
-            u64: event.data as u64,
-        },
-        ..Default::default()
-    };
+    unsafe {
+        *target_ptr = epoll_event {
+            events: event_flags_to_epoll(event.flags),
+            data: epoll_data {
+                u64: event.data as u64,
+            },
+            ..Default::default()
+        };
+    }
     true
 }