Test that the left and right sides of a compound SELECT operator have the same  number of expressions in the expanded expression list before beginning to generate code.

FossilOrigin-Name: 4df852ce26c95d5d23c83dbe9c59d2c3435acddf
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 4812b89..3ebd8de 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3570,6 +3570,7 @@
 void sqlite3ExpirePreparedStatements(sqlite3*);
 int sqlite3CodeSubselect(Parse *, Expr *, int, int);
 void sqlite3SelectPrep(Parse*, Select*, NameContext*);
+void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p);
 int sqlite3MatchSpanName(const char*, const char*, const char*, const char*);
 int sqlite3ResolveExprNames(NameContext*, Expr*);
 void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);