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/sys_ioctl.in.h

@@ -0,0 +1,78 @@
+/* Substitute for and wrapper around <sys/ioctl.h>.
+   Copyright (C) 2008-2017 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, 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/>.  */
+
+#ifndef _@GUARD_PREFIX@_SYS_IOCTL_H
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_SYS_IOCTL_H@
+# @INCLUDE_NEXT@ @NEXT_SYS_IOCTL_H@
+#endif
+
+#ifndef _@GUARD_PREFIX@_SYS_IOCTL_H
+#define _@GUARD_PREFIX@_SYS_IOCTL_H
+
+/* AIX 5.1 and Solaris 10 declare ioctl() in <unistd.h> and in <stropts.h>,
+   but not in <sys/ioctl.h>.
+   But avoid namespace pollution on glibc systems.  */
+#ifndef __GLIBC__
+# include <unistd.h>
+#endif
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+
+/* Declare overridden functions.  */
+
+#if @GNULIB_IOCTL@
+# if @REPLACE_IOCTL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef ioctl
+#   define ioctl rpl_ioctl
+#  endif
+_GL_FUNCDECL_RPL (ioctl, int,
+                  (int fd, int request, ... /* {void *,char *} arg */));
+_GL_CXXALIAS_RPL (ioctl, int,
+                  (int fd, int request, ... /* {void *,char *} arg */));
+# else
+#  if @SYS_IOCTL_H_HAVE_WINSOCK2_H@ || 1
+_GL_FUNCDECL_SYS (ioctl, int,
+                  (int fd, int request, ... /* {void *,char *} arg */));
+#  endif
+_GL_CXXALIAS_SYS (ioctl, int,
+                  (int fd, int request, ... /* {void *,char *} arg */));
+# endif
+_GL_CXXALIASWARN (ioctl);
+#elif @SYS_IOCTL_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS@
+# undef ioctl
+# define ioctl ioctl_used_without_requesting_gnulib_module_ioctl
+#elif defined GNULIB_POSIXCHECK
+# undef ioctl
+# if HAVE_RAW_DECL_IOCTL
+_GL_WARN_ON_USE (ioctl, "ioctl does not portably work on sockets - "
+                 "use gnulib module ioctl for portability");
+# endif
+#endif
+
+
+#endif /* _@GUARD_PREFIX@_SYS_IOCTL_H */
+#endif /* _@GUARD_PREFIX@_SYS_IOCTL_H */