bug#15933: make check not working

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Wed, 20 Nov 2013 13:49:53 -0500
> Cc: 15933@debbugs.gnu.org
> 
> Perhaps -L :foo is not working correctly on mingw?

Why should it?  Observe:

                  ((member argi '("-L" "-directory"))
                   ;; -L :/foo adds /foo to the _end_ of load-path.
                   (let (append)
                     (if (string-match-p
                          "\\`:"  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                          (setq tem (or argval (pop command-line-args-left))))
                         (setq tem (substring tem 1)
                               append t))

It should use path-separator instead of a literal ':'.

(No, you don't need to change anything in test/automated/Makefile,
since the MSYS Bash will automatically convert ':' into ';'.)