diff --git a/lib/Makefile b/lib/Makefile
index d7946ff..6e2cc56 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -174,3 +174,5 @@
       cmd_build_OID_registry = perl $(srctree)/$(src)/build_OID_registry $< $@
 
 clean-files	+= oid_registry_data.c
+
+obj-$(CONFIG_UCS2_STRING) += ucs2_string.o