Fix code I unwittingly broke in b0e2d6592a1f (#14038)
diff --git a/Lib/packaging/tests/support.py b/Lib/packaging/tests/support.py
index 06f06c9..d76d3db 100644
--- a/Lib/packaging/tests/support.py
+++ b/Lib/packaging/tests/support.py
@@ -342,7 +342,7 @@
         srcdir = sysconfig.get_config_var('projectbase')
         path = os.path.join(os.getcwd(), srcdir, 'Modules', 'xxmodule.c')
     else:
-        os.path.join(os.path.dirname(__file__), 'xxmodule.c')
+        path = os.path.join(os.path.dirname(__file__), 'xxmodule.c')
     if os.path.exists(path):
         return path