S9 LIB  (string-locate string1 string2)     ==>  offset | #f
        (string-ci-locate string1 string2)  ==>  offset | #f

        (load-from-library "string-locate.scm")

Attempt to locate the pattern STRING1 in the text STRING2. Return
the offset of the first occurrence of STRING1 in STRING2 or #F,
if STRING2 does not contain STRING1.

This program is based on "A Very Fast Substring Search Algorithm",
Daniel M. Sunday, CACM v33, #8, August 1990 and the
SUBSTRING-SEARCH-MAKER procedure by Ken Dickey (1990).

(string-locate "test" "This is a test string")     ==>  10
(string-locate "TEST" "This is a test string")     ==>  #f
