diff --git a/Makefile.am b/Makefile.am
index 491b4c8f9f..e52b1f742a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -477,7 +477,7 @@ version:
 
 .PHONY: autostyle-ifdefs
 autostyle-ifdefs:
-	$(PYTHON) scripts/maint/annotate_ifdef_directives $(OWNED_TOR_C_FILES)
+	$(PYTHON) scripts/maint/annotate_ifdef_directives.py $(OWNED_TOR_C_FILES)
 
 .PHONY: autostyle-ifdefs
 autostyle-operators:
diff --git a/scripts/maint/annotate_ifdef_directives b/scripts/maint/annotate_ifdef_directives.py
similarity index 100%
rename from scripts/maint/annotate_ifdef_directives
rename to scripts/maint/annotate_ifdef_directives.py