Optimize the degenerate case of a FROM clause table name enclosed all by
itself inside parentheses.  Generate code as if the parentheses did not
exist, rather than the old behavior of manifesting the parenthesized table
into a transient table.  Also, tag every FROM-clause SELECT subquery that is
generated by a parenthesized FROM-clause expression using the SF_NestedFrom
flag.  The new SF_NestedFrom flag is not yet used for anything.

FossilOrigin-Name: 7fecced466d86a66b0b751c5b5608141e134fe2d
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 2b58a80..8a04ab4 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2102,6 +2102,7 @@
 #define SF_UseSorter       0x0040  /* Sort using a sorter */
 #define SF_Values          0x0080  /* Synthesized from VALUES clause */
 #define SF_Materialize     0x0100  /* Force materialization of views */
+#define SF_NestedFrom      0x0200  /* Part of a parenthesized FROM clause */
 
 
 /*
@@ -2814,7 +2815,7 @@
 void sqlite3DropIndex(Parse*, SrcList*, int);
 int sqlite3Select(Parse*, Select*, SelectDest*);
 Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
-                         Expr*,ExprList*,int,Expr*,Expr*);
+                         Expr*,ExprList*,u16,Expr*,Expr*);
 void sqlite3SelectDelete(sqlite3*, Select*);
 Table *sqlite3SrcListLookup(Parse*, SrcList*);
 int sqlite3IsReadOnly(Parse*, Table*, int);