Various 64-bit fixes.
 [rsc] --rw-rw-r-- M 1428987 jmk sys 8788 Jan 28 10:53 sys/src/cmd/cc/scon.c
	/n/sourcesdump/2006/0128/plan9/sys/src/cmd/cc/scon.c:1,5 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/cmd/cc/scon.c:1,18
	  #include "cc.h"
	  
	+ static Node*
	+ acast(Type *t, Node *n)
	+ {
	+ 	if(n->type->etype != t->etype || n->op == OBIT) {
	+ 		n = new1(OCAST, n, Z);
	+ 		if(nocast(n->left->type, t))
	+ 			*n = *n->left;
	+ 		n->type = t;
	+ 	}
	+ 	return n;
	+ }
	+ 
	+ 
	  void
	  evconst(Node *n)
	  {
	/n/sourcesdump/2006/0128/plan9/sys/src/cmd/cc/scon.c:426,435 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/cmd/cc/scon.c:439,446
	  			if(c2 % c1)
	  				continue;
	  			r = trm[j].node;
	- 			if(r->type->etype != et) {
	- 				r = new1(OCAST, r, Z);
	- 				r->type = t;
	- 			}
	+ 			if(r->type->etype != et)
	+ 				r = acast(t, r);
	  			c2 = trm[j].mult/trm[i].mult;
	  			if(c2 != 1 && c2 != -1) {
	  				r = new1(OMUL, r, new(OCONST, Z, Z));
	/n/sourcesdump/2006/0128/plan9/sys/src/cmd/cc/scon.c:438,447 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/cmd/cc/scon.c:449,456
	  				r->right->vconst = c2;
	  			}
	  			l = trm[i].node;
	- 			if(l->type->etype != et) {
	- 				l = new1(OCAST, l, Z);
	- 				l->type = t;
	- 			}
	+ 			if(l->type->etype != et)
	+ 				l = acast(t, l);
	  			r = new1(OADD, l, r);
	  			r->type = t;
	  			if(c2 == -1)
	/n/sourcesdump/2006/0128/plan9/sys/src/cmd/cc/scon.c:468,477 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/cmd/cc/scon.c:477,484
	  		if(c1 == 0)
	  			continue;
	  		r = trm[i].node;
	- 		if(r->type->etype != et || r->op == OBIT) {
	- 			r = new1(OCAST, r, Z);
	- 			r->type = t;
	- 		}
	+ 		if(r->type->etype != et || r->op == OBIT)
	+ 			r = acast(t, r);
	  		if(c1 != 1 && c1 != -1) {
	  			r = new1(OMUL, r, new(OCONST, Z, Z));
	  			r->type = t;
	/n/sourcesdump/2006/0128/plan9/sys/src/cmd/cc/scon.c:576,582 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/cmd/cc/scon.c:583,589
	  
	  	if(n != Z)
	  	if(!typefd[n->type->etype])
	- 	if(!typev[n->type->etype])
	+ 	if(!typev[n->type->etype] || ewidth[TVLONG] == ewidth[TIND])
	  	switch(n->op) {
	  
	  	case OCAST:
 [rsc] --rw-rw-r-- M 1428987 glenda sys 34377 Jan 28 10:53 sys/src/cmd/cc/sub.c
	/n/sourcesdump/2006/0128/plan9/sys/src/cmd/cc/sub.c:684,690 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/cmd/cc/sub.c:684,690
	  	if(n->op == OSUB)
	  	if(i == TIND && j == TIND) {
	  		w = n->right->type->link->width;
	- 		if(w < 1)
	+ 		if(w < 1 || n->left->type->link == T || n->left->type->link->width < 1)
	  			goto bad;
	  		n->type = types[ewidth[TIND] <= ewidth[TLONG]? TLONG: TVLONG];
	  		if(1 && ewidth[TIND] > ewidth[TLONG]){