isdir.m: Make m-file a legacy function (bug #54489) * isdir.m: Note that function is not recommended in docstring. Add 1-time warning about function being obsolete. Add first time BIST test to provoke and suppress warning. * scripts/legacy/module.mk, scripts/miscellaneous/module.mk: Move isdir.m from miscellaneous/ dir to legacy/ dir. * NEWS: Announce change to legacy function. * syscalls.cc (Fstat): Add isfolder to @seealso link. * utils.cc (Fis_absolute_filename, Fis_rooted_relative_filename, Fmake_absolute_filename): Replace isdir with isfolder in @seealso links. * uigetdir.m, uigetfile.m, uiputfile.m, which.m, copyfile.m, mkdir.m, movefile.m, tempdir.m, unpack.m, what.m, __print_parse_opts__.m, compare_plot_demos.m, rundemos.m, runtests.m: Replace instances of isdir with isfolder in core Octave.

--- a/scripts/testfun/runtests.m	Mon Aug 13 11:41:17 2018 -0700
+++ b/scripts/testfun/runtests.m	Mon Aug 13 12:17:58 2018 -0700
@@ -38,7 +38,7 @@
     do_class_dirs = true;
   elseif (nargin == 1)
     dirs = {canonicalize_file_name(directory)};
-    if (isempty (dirs{1}) || ! isdir (dirs{1}))
+    if (isempty (dirs{1}) || ! isfolder (dirs{1}))
       ## Search for directory name in path
       if (directory(end) == '/' || directory(end) == '\')
         directory(end) = [];
@@ -83,7 +83,7 @@
       endif
     elseif (f(1) == "@")
       f = fullfile (directory, f);
-      if (isdir (f))
+      if (isfolder (f))
         dirs(end+1) = f;
       endif
     endif