build: Add Python 3 support (see issue #2856)

tools/compile_ib_files.py

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 from __future__ import print_function
+from __future__ import absolute_import
 import argparse
 import logging
 import os