S9 LIB  (string-split char string)  ==>  list

Split a string into substrings. CHAR is interpreted as a separator.
Return a list containing all coherent sequences of non-separating
characters contained in the given string. When multiple subsequent
separators are found, empty strings will be generated.

(string-split #\: "a::b:c:")  ==>  ("a" "" "b" "c" "")
