Use backtick to check if Mail/queue is empty.
3 hardstatus alwayslastline "%{=b rw}%`%{-}%-Lw%{=b bw}%40L>%n%f %t%{-}%+Lw%<"
4 backtick 0 30 30 $HOME/bin/checkqueue
10 bind -c REGION 2 split
11 bind -c REGION o focus
13 bind -c REGION 0 remove
14 bind x command -c REGION
16 bind -c ENCODING e eval 'encoding eucJP' 'echo "Encoding: eucJP"'
17 bind -c ENCODING s eval 'encoding SJIS' 'echo "Encoding: shift_jis"'
18 bind -c ENCODING j eval 'encoding jis' 'echo "Encoding: iso-2022-jp"'
19 bind -c ENCODING u eval 'encoding UTF-8' 'echo "Encoding: utf-8"'
20 bind e command -c ENCODING