diff --git a/libs/phidget21/Makefile b/libs/phidget21/Makefile
index 035ccfb3b..ccfd443ed 100644
--- a/libs/phidget21/Makefile
+++ b/libs/phidget21/Makefile
@@ -58,7 +58,7 @@ define Build/Compile
 		phidget21internal.h
 	$(MAKE) -C $(PKG_BUILD_DIR)/webservice \
 		$(TARGET_CONFIGURE_OPTS) LDCONFIG="true" \
-		LIBS="-lphidget21 -L../phidget21" \
+		LIBS="-lphidget21 -lpthread -ldl -L../phidget21" \
 		CFLAGS="$(TARGET_CFLAGS) -static -D_LINUX -I. -I../phidget21 -I../phidget21/utils" \
 		webservice21
 endef