Locate-Path

(locate-path file dir1 dir2 ...) -> string or null

Given a file-name, and a list of directory paths, returns the path of the
first file that matches (string-append dir *path-sep* file).

Example:

>> (locate-path "mosc.ms" "lib" "core")
:: "lib/mosc.ms"
>> (locate-path "mosc.ms" "*")
:: null