Only nuke $objtype.
 [rsc] --rw-rw-r-- M 129339 glenda sys 745 Dec 12 09:06 sys/src/libc/mkfile
	/n/sourcesdump/2005/1212/plan9/sys/src/libc/mkfile:1,9 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libc/mkfile:1,10
	  </$objtype/mkfile
	  
	- DIRS=9sys 9syscall fmt port $CPUS
	+ PORTDIRS=9sys 9syscall fmt port
	+ DIRS=$PORTDIRS $CPUS
	  
	  all install:V:
	- 	for(i in 9sys 9syscall fmt port $objtype)@{
	+ 	for(i in $PORTDIRS $objtype)@{
	  		echo $i
	  		cd $i
	  		mk $MKFLAGS install
	/n/sourcesdump/2005/1212/plan9/sys/src/libc/mkfile:17,26 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libc/mkfile:18,33
	  	}
	  
	  nuke:V:
	- 	for(i in $DIRS)@{
	+ 	for(i in $PORTDIRS $objtype)@{
	  		echo $i
	  		cd $i
	  		mk $MKFLAGS nuke
	+ 	}
	+ 	# do not nuke other objtypes
	+ 	for(i in $CPUS)@{
	+ 		echo $i
	+ 		cd $i
	+ 		mk $MKFLAGS clean
	  	}
	  
	  update:V:
 [rsc] --rw-rw-r-- M 129339 glenda sys 962 Dec 12 17:27 sys/src/libmp/mkfile
	/n/sourcesdump/2005/1212/plan9/sys/src/libmp/mkfile:4,15 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libmp/mkfile:4,18
	  
	  default:V:	all
	  
	- install clean nuke all:V:
	+ install clean all:V:
	  	for(i in port $objtype)@{
	  		echo $i
	  		cd $i
	  		mk $MKFLAGS $target
	  	}
	+ 
	+ nuke:V: clean
	+ 	rm -f /$objtype/lib/libmp.a
	  
	  update:V:
	  	for(i in port $CPUS)@{
 [rsc] --rw-rw-r-- M 129339 glenda sys 554 Dec 12 17:28 sys/src/libsec/mkfile
	/n/sourcesdump/2005/1212/plan9/sys/src/libsec/mkfile:1,6 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libsec/mkfile:1,6
	  </$objtype/mkfile
	  
	- DIRS=port 386 alpha arm mips power
	+ DIRS=port $CPUS
	  
	  default:V:	all
	  
	/n/sourcesdump/2005/1212/plan9/sys/src/libsec/mkfile:11,17 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libsec/mkfile:11,17
	  		mk $MKFLAGS $target
	  	}
	  
	- clean nuke:V:
	+ clean:V:
	  	for(i in $DIRS)@{
	  		echo $i
	  		cd $i
	/n/sourcesdump/2005/1212/plan9/sys/src/libsec/mkfile:18,23 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libsec/mkfile:18,26
	  		mk $MKFLAGS $target
	  	}
	  
	+ nuke:V: clean
	+ 	rm -f /$objtype/lib/libsec.a
	+ 
	  update:V:
	  	for(i in $DIRS)@{
	  		echo $i
	/n/sourcesdump/2005/1212/plan9/sys/src/libsec/mkfile:30,38 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/libsec/mkfile:33,41
	  	for(objtype in $CPUS) mk $MKFLAGS install
	  
	  everything:V:
	- 	rm -f */*.[012456789kvx]
	+ 	rm -f */*.[012456789kqv]
	  	for(objtype in 386)@{
	  		echo $objtype
	  		mk $MKFLAGS install
	  	}
	- 	rm -f */*.[012456789kvx]
	+ 	rm -f */*.[012456789kqv]