missing header

Index: src/Core/OXPVerifier/OOOXPVerifierStage.m
--- src/Core/OXPVerifier/OOOXPVerifierStage.m.orig
+++ src/Core/OXPVerifier/OOOXPVerifierStage.m
@@ -48,6 +48,9 @@ SOFTWARE.
 
 #import "OOOXPVerifierStageInternal.h"
 
+#include <assert.h>
+
+
 #if OO_OXP_VERIFIER_ENABLED
 
 @interface OOOXPVerifierStage (OOPrivate)
