(defun locate-file (filename path &optional suffixes predicate)
"Search for FILENAME through PATH.
-If found, return the absolute file name of FILENAME, with its suffixes;
-otherwise return nil.
+If found, return the absolute file name of FILENAME; otherwise
+return nil.
PATH should be a list of directories to look in, like the lists in
`exec-path' or `load-path'.
If SUFFIXES is non-nil, it should be a list of suffixes to append to