diff --git a/libcxx/utils/libcxx/test/config.py b/libcxx/utils/libcxx/test/config.py
--- a/libcxx/utils/libcxx/test/config.py
+++ b/libcxx/utils/libcxx/test/config.py
@@ -1205,6 +1205,6 @@
         if 'PATH' not in dest_env:
             dest_env['PATH'] = new_path
         else:
-            split_char = ';' if self.target_info.is_windows() else ':'
+            split_char = ';' if platform.system() == 'Windows' else ':'
             dest_env['PATH'] = '%s%s%s' % (new_path, split_char,
                                            dest_env['PATH'])