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.

^settings\.mk
^usr/
^log/
^pkg/
^built-packages/
^installed-packages/
^wip/
^tmp-.*/

^autom4te\.cache/
^configure
^config\.status
^config\.log
^Makefile
^cmake-toolchain-file\.stamp

^cross-tools/
^gnuplot/
^octave/
^tools/makeinst-script\.sh
^tools/set-mxe-env\.sh