Check in implementation of foreign key constraints.

FossilOrigin-Name: d5d399811876391642937edeb9e8434dd9e356f5

src/vdbeInt.h

@@ -315,6 +315,7 @@ struct Vdbe {
   int aCounter[2];        /* Counters used by sqlite3_stmt_status() */
   char *zSql;             /* Text of the SQL statement that generated this */
   void *pFree;            /* Free this when deleting the vdbe */
+  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
   int iStatement;         /* Statement number (or 0 if has not opened stmt) */
 #ifdef SQLITE_DEBUG
   FILE *trace;            /* Write an execution trace here, if not NULL */
@@ -387,6 +388,12 @@ int sqlite3VdbeFrameRestore(VdbeFrame *);
 int sqlite3VdbeReleaseBuffers(Vdbe *p);
 #endif
 
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+int sqlite3VdbeCheckDeferred(Vdbe *);
+#else
+# define sqlite3VdbeCheckDeferred(p) 0
+#endif
+
 #ifndef SQLITE_OMIT_SHARED_CACHE
 void sqlite3VdbeMutexArrayEnter(Vdbe *p);
 #else