diff --git a/arduino-mk/Arduino.mk b/arduino-mk/Arduino.mk
index b1c79b6..056ab13 100644
--- a/arduino-mk/Arduino.mk
+++ b/arduino-mk/Arduino.mk
@@ -721,9 +721,9 @@ $(OBJDIR)/libs/%.o: $(USER_LIB_PATH)/%.c
 	$(CC) -MMD -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 ifdef COMMON_DEPS
-	COMMON_DEPS := $(COMMON_DEPS) Makefile
+    COMMON_DEPS := $(COMMON_DEPS) Makefile
 else
-	COMMON_DEPS := Makefile
+    COMMON_DEPS := Makefile
 endif
 
 # normal local sources