diff --git a/src/fileio.c b/src/fileio.c
index b0ef3d4e91f..52ca8b6297e 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2697,7 +2697,7 @@ See `file-symlink-p' to distinguish symlinks.  */)
 bool
 file_directory_p (Lisp_Object file)
 {
-#ifdef WINDOWSNT
+#ifdef DOS_NT
   /* This is cheaper than 'stat'.  */
   return faccessat (AT_FDCWD, SSDATA (file), D_OK, AT_EACCESS) == 0;
 #else