...
add_dir_to_list(self.compiler.include_dirs, '/usr/local/include')
add_dir_to_list(self.compiler.library_dirs, '/usr/local/lib')
to:
add_dir_to_list(self.compiler.include_dirs, '/usr/local/include')
add_dir_to_list(self.compiler.library_dirs, '/usr/local/lib')
add_dir_to_list(self.compiler.library_dirs, '/usr/lib')
add_dir_to_list(self.compiler.include_dirs, '/usr/include')
...