Update readline to 8.0. * src/readline.mk: Update version and checksum. * src/readline-1-binding.patch, src/readline-1-display.patch, src/readline-1-input.patch, src/readline-1-paste.patch, src/readline-1-sigwinch.patch, src/readline-2-event.patch: Remove patches that are no longer necessary. * src/readline-1-fixes.patch: Add patch from mxe.cc. * dist-files.mk: Update files.

## System-wide startup file for Octave.
##
## This file should contain any commands that should be executed each
## time Octave starts for every user at this site.
EXEC_PATH (cstrcat (fullfile (OCTAVE_HOME, 'notepad++'), pathsep, EXEC_PATH));
EXEC_PATH (cstrcat (fullfile (OCTAVE_HOME, 'bin'), pathsep, EXEC_PATH));
EDITOR (fullfile (OCTAVE_HOME, 'notepad++', 'notepad++.exe'));