Merge all of the latest trunk changes into the sessions branch.

FossilOrigin-Name: a9bcb432f58b96f079a73c456efd4851c582221e

src/vdbe.h

@@ -83,6 +83,7 @@ struct SubProgram {
   int nOp;                      /* Elements in aOp[] */
   int nMem;                     /* Number of memory cells required */
   int nCsr;                     /* Number of cursors required */
+  int nOnce;                    /* Number of OP_Once instructions */
   void *token;                  /* id that may be used to recursive triggers */
   SubProgram *pNext;            /* Next sub-program already visited */
 };