diff --git a/Makefile b/Makefile
index b20810f3..8fa27a07 100644
--- a/Makefile
+++ b/Makefile
@@ -301,18 +301,20 @@ update-checksum-%:
 	$(error package $* not found in index.html))
 
 .PHONY: cleanup-style
+define CLEANUP_STYLE
+    @$(SED) ' \
+        s/\r//g; \
+        s/[ \t]\+$$//; \
+        s,^#!/bin/bash$$,#!/usr/bin/env bash,; \
+        $(if $(filter %Makefile,$(1)),,\
+            s/\t/    /g; \
+        ) \
+    ' < $(1) > $(TOP_DIR)/tmp-cleanup-style; \
+    diff -u $(1) $(TOP_DIR)/tmp-cleanup-style >/dev/null \
+        || { echo '[cleanup] $(1)'; \
+             cp $(TOP_DIR)/tmp-cleanup-style $(1); }; \
+    rm -f $(TOP_DIR)/tmp-cleanup-style
+
+endef
 cleanup-style:
-	@$(foreach FILE,$(wildcard $(addprefix $(TOP_DIR)/,Makefile index.html CNAME src/*.mk src/*test.* tools/*)),\
-            $(SED) ' \
-                s/\r//g; \
-                s/[ \t]\+$$//; \
-                s,^#!/bin/bash$$,#!/usr/bin/env bash,; \
-                $(if $(filter %Makefile,$(FILE)),,\
-                    s/\t/    /g; \
-                ) \
-            ' < $(FILE) > $(TOP_DIR)/tmp-cleanup-style; \
-            diff -u $(FILE) $(TOP_DIR)/tmp-cleanup-style >/dev/null \
-                || { echo '[cleanup] $(FILE)'; \
-                     cp $(TOP_DIR)/tmp-cleanup-style $(FILE); }; \
-            rm -f $(TOP_DIR)/tmp-cleanup-style; \
-        )
+	$(foreach FILE,$(wildcard $(addprefix $(TOP_DIR)/,Makefile index.html CNAME src/*.mk src/*test.* tools/*)),$(call CLEANUP_STYLE,$(FILE)))