Add missing #[cfg(target_pointer_width)].

Author: m-ou-se

src/addr.rs

@@ -88,6 +88,11 @@ impl VirtAddr {
     }
 
     /// Creates a virtual address from the given pointer
+    // cfg(target_pointer_width = "32") is only here for backwards
+    // compatibility: Earlier versions of this crate did not have any `cfg()`
+    // on this function. At least for 32- and 64-bit we know the `as u64` cast
+    // doesn't truncate.
+    #[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
     pub fn from_ptr<T>(ptr: *const T) -> Self {
         Self::new(ptr as u64)
     }