Instead of using a lemon %fallback directive, have the tokenizer try to figure
out whether an instance of "WINDOW" should be TK_WINDOW or TK_ID.

FossilOrigin-Name: 022079cb0d67be5ac0a50dd9a4d41ee55ce8df681ecd0a544170d75fc8649978
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 9fab8f5..448918a 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -4299,6 +4299,7 @@
   void sqlite3ParserFree(void*, void(*)(void*));
 #endif
 void sqlite3Parser(void*, int, Token);
+int sqlite3ParserFallback(int);
 #ifdef YYTRACKMAXSTACKDEPTH
   int sqlite3ParserStackPeak(void*);
 #endif