diff --git a/tests/libtest/Makefile.inc b/tests/libtest/Makefile.inc
index 5c80f88c95..9bf035e404 100644
--- a/tests/libtest/Makefile.inc
+++ b/tests/libtest/Makefile.inc
@@ -409,7 +409,7 @@ lib676_SOURCES = lib676.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib676_LDADD = $(TESTUTIL_LIBS)
 lib676_CPPFLAGS = $(AM_CPPFLAGS)
 
-lib678_SOURCES = lib678.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib678_SOURCES = lib678.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS) $(MULTIBYTE)
 lib678_LDADD = $(TESTUTIL_LIBS)
 lib678_CPPFLAGS = $(AM_CPPFLAGS)