fix compile error

vm/vm.c

@@ -63,7 +63,7 @@ void
 newstack(int sz)
 {
 	Stack *s = calloc(1, sizeof(s)+sz);
-	R.EX = s->stack;
+	R.EX = s;
 	R.TS = s->stack + sz;
 	R.SP = s->fu + sz;
 	R.FP = s->fu;
@@ -133,14 +133,13 @@ OP(ret) {
 	R.FP = f->fp;
 	if(R.FP == NULL){
 		printf("result %ld\n", W(d));
-		WORD *p = end;
 		exit(0);
 	}
 	R.SP = (u8*)f;
 	R.PC = f->lr;
 
 	u8 *x = (u8*)f-IBY2WD*4;
-	Stack *s = x;
+	Stack *s = (Stack*)x;
 	R.SP = s->SP;
 	R.TS = s->TS;
 	R.EX = s->EX;

vm/vm.h

@@ -45,7 +45,7 @@ union Stack
 		int sz;
 		u8 *SP;
 		u8 *TS;
-		u8 *EX;
+		Stack *EX;
 		union{
 			u8 fu[1];
 			Frame fr[1];
@@ -59,7 +59,7 @@ struct REG
 	u8 *FP;
 	u8 *SP;
 	u8 *TS;
-	u8 *EX;
+	Stack *EX;
 	void *s, *d, *m;
 	WORD t, dt ,mt;
 };