Emacs-22
 (split-string " a b  c d " " ")
 => ("" "a" "b" "" "c" "d" "")
  
 (split-string "     " " ")
 => ("" "" "" "" "" "")
  
 (split-string " " " ")
 => ("" "")
Emacs-20,21
 (split-string " a b  c d " " ")
 => ("a" "b" "" "c" "d")
  
 (split-string "     " " ")
 => ("" "" "" "")
  
 (split-string " " " ")
 => nil
Emacs-22 の挙動を期待していたので、egg-anthy-split-string() を定義して差異を吸収。
Emacs-22 の split-string() は(たしか)XEmacs と同じ動きだと思ったんだけど、Emacs-20 を使っていた当時は XEmacs の split-string() を見て『変なの』と思ったのは、今となっては内緒 ^^;;;