Try to make pointer stringification portable

tests/gumjs/script.c

@@ -10918,13 +10918,11 @@ TESTCASE (java_api_is_embedded)
 
 TESTCASE (cloaked_items_can_be_queried_added_and_removed)
 {
-  char * buffer = (char *) malloc (64);
+  void * buffer = malloc (64);
 
   COMPILE_AND_LOAD_SCRIPT (
-    "const bufferAt = '%p';"
-    "send(bufferAt);"
-    "const x = ptr(bufferAt);"
-    //"send(Cloak.hasRangeContaining(x) === false);"
+    "const x = ptr('0x%" G_GINT64_MODIFIER "x');"
+    "send(Cloak.hasRangeContaining(x) === false);"
     "send(Process.findRangeByAddress(x) !== null);"
     "send(Cloak.clipRange(x, 64) === null);"
     "Cloak.addRange(x, 64);"
@@ -10947,7 +10945,7 @@ TESTCASE (cloaked_items_can_be_queried_added_and_removed)
     "send(Cloak.hasFileDescriptor(fd));"
     "Cloak.removeFileDescriptor(fd);"
     "send(!Cloak.hasFileDescriptor(fd));",
-    buffer
+    GPOINTER_TO_SIZE (buffer)
   );
   EXPECT_SEND_MESSAGE_WITH ("true");
   EXPECT_SEND_MESSAGE_WITH ("true");