diff --git a/libasn1parser/asn1p_constr.h b/libasn1parser/asn1p_constr.h
index d3756780b1c46ea0c830d9b5b1a13d6c215a6203..c83d58bd3409f2b5ac010865b3004138b9455a97 100644
--- a/libasn1parser/asn1p_constr.h
+++ b/libasn1parser/asn1p_constr.h
@@ -57,6 +57,7 @@ typedef struct asn1p_constraint_s {
 	int el_size;	/* Size of the allocated (elements) */
 
 	int _lineno;	/* Position in a source file */
+	int _compile_mark;	/* Marker used by the compiler */
 } asn1p_constraint_t;
 
 /* Human-readable constraint type description */