Allow $installmode plan9.ini variable to avoid trying graphics mode.
Redundant with simply typing "no" to the graphics prompts.
 [rsc] --rw-rw-r-- M 411683 glenda sys 2209 Sep 10 08:27 sys/lib/dist/pc/sub/termrc
	/n/sourcesdump/2005/0910/plan9/sys/lib/dist/pc/sub/termrc:53,58 - 
	/n/sourcesdump/2005/0911/plan9/sys/lib/dist/pc/sub/termrc:53,78
	  
	  aux/vmware
	  
	+ # configure loopback device without touching /net/ndb
	+ {
	+ 	echo bind loopback /dev/null
	+ 	echo add 127.0.0.1 255.255.255.0 
	+ } >/net/ipifc/clone
	+ 
	+ if(~ $installmode ask){
	+ 	echo -n 'install mode is (text, graphics)[graphics]: '
	+ 	installmode=`{read}
	+ 	if(~ $#installmode 0)
	+ 		installmode=graphics
	+ }
	+ if(~ $installmode text){
	+ 	mouseport=()
	+ 	vgasize=()
	+ 	monitor=()
	+ }
	+ if not
	+ 	installmode=graphics
	+ 	
	  if(~ $mouseport ask){
	  	echo -n 'mouseport is (ps2, ps2intellimouse, 0, 1, 2)[ps2]: '
	  	mouseport=`{read}
	/n/sourcesdump/2005/0910/plan9/sys/lib/dist/pc/sub/termrc:71,77 - 
	/n/sourcesdump/2005/0911/plan9/sys/lib/dist/pc/sub/termrc:91,96
	  	if(~ $#monitor 0)
	  		monitor=xga
	  }
	- 
	  if(~ $#mouseport 1) {
	  	aux/mouse $mouseport
	  	if(~ $#vgasize 1 && ! ~ $vgasize '') {
	/n/sourcesdump/2005/0910/plan9/sys/lib/dist/pc/sub/termrc:86,95 - 
	/n/sourcesdump/2005/0911/plan9/sys/lib/dist/pc/sub/termrc:105,108
	  			echo -n 'hwblank off' >'#v/vgactl' >[2]/dev/null
	  	}
	  }
	- 
	- # configure loopback device without touching /net/ndb
	- {
	- 	echo bind loopback /dev/null
	- 	echo add 127.0.0.1 255.255.255.0 
	- } >/net/ipifc/clone
	  

Exit with error status on errors.
 [rsc] --rw-rw-r-- M 411683 glenda sys 11753 Sep 10 10:02 sys/src/cmd/dd.c
	/n/sourcesdump/2005/0910/plan9/sys/src/cmd/dd.c:51,57 - 
	/n/sourcesdump/2005/0911/plan9/sys/src/cmd/dd.c:51,57
	  void	ebcdic(int cc);
	  void	ibm(int cc);
	  void	block(int cc);
	- void	term(void);
	+ void	term(char*);
	  void	stats(void);
	  
	  #define	iskey(s)	((key[0] == '-') && (strcmp(key+1, s) == 0))
	/n/sourcesdump/2005/0910/plan9/sys/src/cmd/dd.c:248,254 - 
	/n/sourcesdump/2005/0911/plan9/sys/src/cmd/dd.c:248,254
	  			perror("read");
	  			if((cflag&NERR) == 0) {
	  				flsh();
	- 				term();
	+ 				term("errors");
	  			}
	  			ibc = 0;
	  			for(c=0; c<ibs; c++)
	/n/sourcesdump/2005/0910/plan9/sys/src/cmd/dd.c:258,264 - 
	/n/sourcesdump/2005/0911/plan9/sys/src/cmd/dd.c:258,264
	  			stats();
	  		}else if(ibc == 0 && --files<=0) {
	  			flsh();
	- 			term();
	+ 			term(nil);
	  		}
	  		if(ibc != ibs) {
	  			nipr++;
	/n/sourcesdump/2005/0910/plan9/sys/src/cmd/dd.c:300,306 - 
	/n/sourcesdump/2005/0911/plan9/sys/src/cmd/dd.c:300,306
	  			if(c > 0)
	  				++nopr;
	  			perror("write");
	- 			term();
	+ 			term("errors");
	  		}
	  		if(obc == obs)
	  			nofr++;
	/n/sourcesdump/2005/0910/plan9/sys/src/cmd/dd.c:541,551 - 
	/n/sourcesdump/2005/0911/plan9/sys/src/cmd/dd.c:541,550
	  }
	  
	  void
	- term(void)
	+ term(char *status)
	  {
	- 
	  	stats();
	- 	exits(0);
	+ 	exits(status);
	  }
	  
	  void
 [sys] --rwxrwxr-x M 411683 glenda sys 45398 Sep 10 23:09 386/bin/dd
	/sys/src/cmd/dd.c:flsh
	/sys/src/cmd/dd.c:main
	/sys/src/cmd/dd.c:number
	/sys/src/cmd/dd.c:stats
	/sys/src/cmd/dd.c:term