the following should work:

	; lookman größter
	man 7 juke # juke(7)

Reference: /n/atom/patch/applied2013/lookmanrune
Date: Thu Dec  5 13:05:25 CET 2013
Signed-off-by: quanstro@quanstro.net

--- /rc/bin/lookman	Thu Dec  5 13:04:46 2013
+++ /rc/bin/lookman	Thu Dec  5 13:04:47 2013
@@ -14,7 +14,7 @@
 	exit note
 }
 
-*=`{echo $*|tr A-Z a-z|tr -dc 'a-z0-9_. \012'}	# fold case, delete funny chars
+*=`{echo $*|rune/case|tr -dc 'a-z0-9_. \012 -􏿿'}	# fold case, delete funny chars
 if(~ $#* 0){
 	echo Usage: lookman key ... >/fd/2
 	exit usage
--- /sys/lib/man/lookman/mkindex	Thu Dec  5 13:04:47 2013
+++ /sys/lib/man/lookman/mkindex	Thu Dec  5 13:04:48 2013
@@ -4,7 +4,7 @@
 for(i in /sys/man/[0-9]*/[a-z0-9:]*){
 	p=`{echo $i | sed 's@/sys/man/\([^ ]\)/\([^ ]*\)$@\2(\1)@'}
 	deroff -w_ < $i |
-	tr 'A-Z' 'a-z' |
+	rune/case |
 	sort -u |
 	comm -23 - junkwords |
 	sed 's@$@	'$p'@' >>index		# stick file name on end of line