Use new man flags in plumber.
 [rsc] --rw-rw-r-- M 1487869 glenda sys 2877 Jan 29 12:21 sys/lib/plumb/basic
	/n/sourcesdump/2006/0129/plan9/sys/lib/plumb/basic:86,92 - 
	/n/sourcesdump/2006/0130/plan9/sys/lib/plumb/basic:86,92
	  # man index entries are synthesized
	  type is text
	  data matches '([a-zA-Z¡-￿0-9_\-./]+)\(([1-8])\)'
	- plumb start rc -c 'man '$2' '$1' >[2=1] | plumb -i -d edit -a ''action=showdata filename=/man/'$1'('$2')'''
	+ plumb start rc -c 'man -S -b '$2' '$1'
	  
	  # start rule for images without known suffixes
	  dst is image