If the SQLITE_ENABLE_CURSOR_HINTS macro is defined, then invoke the
sqlite3BtreeCursorHint() interface to provide hints to the storage engine
about rows that need not be returned.  Hints can be disabled using
SQLITE_TESTCTRL_OPTIMIZATIONS with SQLITE_CursorHints (0x2000).  Cursor
hints are not used by the built-in storage engine of SQLite but might
be useful to applications that provide their own storage engine.  The
current code is work-in-progrss and contains bugs.

FossilOrigin-Name: 3a9bec524ef2de44028b4058e67dc962082888d3
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 8bf05a9..45d78f5 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1064,6 +1064,7 @@
 #define SQLITE_OmitNoopJoin   0x0400   /* Omit unused tables in joins */
 #define SQLITE_Stat3          0x0800   /* Use the SQLITE_STAT3 table */
 #define SQLITE_AdjustOutEst   0x1000   /* Adjust output estimates using WHERE */
+#define SQLITE_CursorHints    0x2000   /* Add OP_CursorHint opcodes */
 #define SQLITE_AllOpts        0xffff   /* All optimizations */
 
 /*