includes/std: Added ptr helpers

includes/libstd/ptr.pat

@@ -0,0 +1,15 @@
+namespace std::ptr {
+
+    fn relative_to_pointer(u128 offset) {
+        return $ + offset;
+    };
+
+    fn relative_to_parent(u128 offset) {
+        return addressof(parent) + offset;
+    };
+
+    fn relative_to_end(u128 offset) {
+        return std::mem::size() - offset;
+    };
+
+}