Fix 'directory-file-name' on DOS_NT systems as well

* src/fileio.c (directory_file_name) [DOS_NT]: Fix the DOS_NT case
to be consistent with last change.

* test/src/fileio-tests.el (fileio-tests--odd-symlink-chars):
Disable on MS-Windows.
(fileio-tests--directory-file-name-dos-nt)
(fileio-tests--file-name-as-directory-dos-nt): New tests.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 9df3b1bedae..a1cea94c0b6 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -572,7 +572,7 @@ directory_file_name (char *dst, char *src, ptrdiff_t srclen, bool multibyte)
   if (! (srclen == 2 && IS_DIRECTORY_SEP (src[0])))
     while (srclen > 1
 #ifdef DOS_NT
-           && !IS_ANY_SEP (src[srclen - 2])
+           && !(srclen > 2 && IS_DEVICE_SEP (src[srclen - 2]))
 #endif
            && IS_DIRECTORY_SEP (src[srclen - 1]))
       srclen--;