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/lib/getopt.in.h

@@ -0,0 +1,61 @@
+/* Declarations for getopt.
+   Copyright (C) 1989-2017 Free Software Foundation, Inc.
+   This file is part of gnulib.
+   Unlike most of the getopt implementation, it is NOT shared
+   with the GNU C Library, which supplies a different version of
+   this file.
+
+   gnulib 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.
+
+   gnulib 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 gnulib; if not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef _@GUARD_PREFIX@_GETOPT_H
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+/* The include_next requires a split double-inclusion guard.  We must
+   also inform the replacement unistd.h to not recursively use
+   <getopt.h>; our definitions will be present soon enough.  */
+#if @HAVE_GETOPT_H@
+# define _GL_SYSTEM_GETOPT
+# @INCLUDE_NEXT@ @NEXT_GETOPT_H@
+# undef _GL_SYSTEM_GETOPT
+#endif
+
+#define _@GUARD_PREFIX@_GETOPT_H 1
+
+/* Standalone applications should #define __GETOPT_PREFIX to an
+   identifier that prefixes the external functions and variables
+   defined in getopt-core.h and getopt-ext.h.  When this happens,
+   include the headers that might declare getopt so that they will not
+   cause confusion if included after this file (if the system had
+   <getopt.h>, we have already included it).  */
+#if defined __GETOPT_PREFIX
+# if !@HAVE_GETOPT_H@
+#  define __need_system_stdlib_h
+#  include <stdlib.h>
+#  undef __need_system_stdlib_h
+#  include <stdio.h>
+#  include <unistd.h>
+# endif
+#endif
+
+/* The definition of _GL_ARG_NONNULL is copied here.  */
+
+#include <getopt-cdefs.h>
+#include <getopt-pfx-core.h>
+#include <getopt-pfx-ext.h>
+
+#endif /* _@GUARD_PREFIX@_GETOPT_H */