Remove library on mk nuke.
 [rsc] --rw-rw-r-- M 129339 glenda sys 665 Dec 12 07:22 sys/src/cmd/mksyslib
	/n/sourcesdump/2005/1212/plan9/sys/src/cmd/mksyslib:34,40 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/cmd/mksyslib:34,40
	  	rm -f $stem.[$OS] [$OS].$stem $stem.acid $stem
	  
	  nuke:V:
	- 	rm -f *.[$OS] [$OS].out $CLEANFILES
	+ 	rm -f *.[$OS] [$OS].out $CLEANFILES $LIB
	  
	  %.acid: %.$O $HFILES
	  	$CC $CFLAGS -a $stem.c >$target