diff --git a/src/libopensc/p15emu-westcos.c b/src/libopensc/p15emu-westcos.c
index a2a95f54..3310dc89 100644
--- a/src/libopensc/p15emu-westcos.c
+++ b/src/libopensc/p15emu-westcos.c
@@ -29,6 +29,8 @@
 #include "cardctl.h"
 #include "common/compat_strlcpy.h"
 
+int sc_pkcs15emu_westcos_init_ex(sc_pkcs15_card_t *, sc_pkcs15emu_opt_t *);
+
 static int sc_pkcs15emu_westcos_init(sc_pkcs15_card_t * p15card)
 {
 	int i, r;