diff --git a/lib/swm050/Makefile b/lib/swm050/Makefile
index fc2f89d1..977f5f74 100644
--- a/lib/swm050/Makefile
+++ b/lib/swm050/Makefile
@@ -32,7 +32,8 @@ TGT_CFLAGS	= -Os \
 TGT_CFLAGS      += $(DEBUG_FLAGS)
 TGT_CFLAGS	+= $(STANDARD_FLAGS)
 ARFLAGS		= rcs
-OBJS		= gpio.o
+
+OBJS += gpio.o
 
 VPATH += ../cm3