Initial code to make shadow tables read-only to ordinary SQL. The now

xShadowName method is added to the sqlite3_module object and is used
to identify potential shadow tables.  The SQLITE_PREPARE_SHADOW argument
to sqlite3_prepare_v3() is defined.  It is designed to permit writing to
shadow tables, but is currently an unused placeholder.

FossilOrigin-Name: 31942b3dd3f66eb0d9977bf1cadc2f2d7be7967cce2b55784be0b939dfef1985

src/sqliteInt.h

@@ -2001,6 +2001,7 @@ struct Table {
 #define TF_StatsUsed       0x0100    /* Query planner decisions affected by
                                      ** Index.aiRowLogEst[] values */
 #define TF_HasNotNull      0x0200    /* Contains NOT NULL constraints */
+#define TF_Shadow          0x0400    /* True for a shadow table */
 
 /*
 ** Test to see whether or not a table is a virtual table.  This is