D7: editor multi-cursor support

Add secondary_cursors field to Editor with insert_char_multi,
delete_back_multi, delete_forward_multi methods. Right-to-left
processing ensures position shifts don't corrupt earlier insertions.

7 new tests: add/clear, all_positions, insert, delete_back,
delete_forward, unicode, duplicate-add.

local/recipes/tools/diffutils/source/gnulib-tests/test-getopt-gnu.c

@@ -0,0 +1,45 @@
+/* Test of command line argument processing.
+   Copyright (C) 2009-2017 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2009.  */
+
+#include <config.h>
+
+/* None of the files accessed by this test are large, so disable the
+   ftell link warning if we are not using the gnulib ftell module.  */
+#define _GL_NO_LARGE_FILES
+
+/* POSIX and glibc provide the getopt() function in <unistd.h>, see
+   http://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html
+   https://www.gnu.org/software/libc/manual/html_node/Using-Getopt.html
+   But gnulib provides the getopt() function in <getopt.h>, not in <unistd.h>.
+   This is what we are testing here.  */
+#include <getopt.h>
+
+#ifndef __getopt_argv_const
+# define __getopt_argv_const const
+#endif
+#include "signature.h"
+SIGNATURE_CHECK (getopt_long, int, (int, char *__getopt_argv_const *,
+                                    char const *, struct option const *,
+                                    int *));
+SIGNATURE_CHECK (getopt_long_only, int, (int, char *__getopt_argv_const *,
+                                         char const *, struct option const *,
+                                         int *));
+
+#define TEST_GETOPT_GNU 1
+#define TEST_GETOPT_TMP_NAME "test-getopt-gnu.tmp"
+#include "test-getopt-main.h"