Fix methods inherited from Any in interop value types

Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt

@@ -5,6 +5,8 @@ package kotlinx.cinterop
  * Subtypes are supposed to represent interpretations of the pointed data or code.
  *
  * This interface is likely to be handled by compiler magic and shouldn't be subtyped by arbitrary classes.
+ *
+ * TODO: the behavior of [equals], [hashCode] and [toString] differs on Native and JVM backends.
  */
 interface NativePointed {
     val rawPtr: NativePtr

Interop/Runtime/src/native/kotlin/kotlinx/cinterop/NativeTypes.kt

@@ -4,6 +4,14 @@ import konan.internal.Intrinsic
 
 class NativePtr private constructor() {
     @Intrinsic external operator fun plus(offset: Long): NativePtr
+
+    @Intrinsic private external fun toLong(): Long
+
+    override fun equals(other: Any?) = (other is NativePtr) && konan.internal.areEqualByValue(this, other)
+
+    override fun hashCode() = this.toLong().hashCode()
+
+    override fun toString() = this.toLong().toString() // TODO: format as hex.
 }
 
 inline val nativeNullPtr: NativePtr