Add the new sqlite3.mDbFlags field. Factor out bits of sqlite3.flags that

do not interact with PRAGMA statements into sqlite3.mDbFlags.

FossilOrigin-Name: 3808a00f06d372cc531da039d97bd974e4a6576a30cf63bf562f83f186b313b3

src/trigger.c

@@ -585,7 +585,7 @@ void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
       *pp = (*pp)->pNext;
     }
     sqlite3DeleteTrigger(db, pTrigger);
-    db->flags |= SQLITE_InternChanges;
+    db->mDbFlags |= DBFLAG_SchemaChange;
   }
 }