Replace bison 3.4.2 with bison 3.6.4

steps/bison-3.6.4/import-gnulib.sh

@@ -0,0 +1,96 @@
+#!/bin/bash
+
+# SPDX-FileCopyrightText: 2021 Samuel Tyler <samuel@samuelt.me>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+../gnulib-ffbb0ce/gnulib-tool --import --local-dir=gl \
+ --lib=libbison \
+ --source-base=lib \
+ --m4-base=m4 \
+ --po-base=gnulib-po \
+ --doc-base=doc \
+ --tests-base=tests \
+ --aux-dir=build-aux \
+ --makefile-name=gnulib.mk \
+ --conditional-dependencies \
+ --no-libtool \
+ --macro-prefix=gl \
+ --po-domain=bison \
+ argmatch \
+ array-list \
+ assert \
+ assure \
+ bitsetv \
+ c-strcase \
+ calloc-posix \
+ close \
+ closeout \
+ config-h \
+ configmake \
+ dirname \
+ error \
+ extensions \
+ fdl \
+ fopen-safer \
+ fprintf-posix \
+ fstrcmp \
+ getopt-gnu \
+ gettext-h \
+ git-version-gen \
+ gitlog-to-changelog \
+ gpl-3.0 \
+ intprops \
+ inttypes \
+ isnan \
+ javacomp-script \
+ javaexec-script \
+ ldexpl \
+ libtextstyle-optional \
+ malloc-gnu \
+ mbfile \
+ mbswidth \
+ non-recursive-gnulib-prefix-hack \
+ obstack \
+ obstack-printf \
+ perror \
+ printf-posix \
+ progname \
+ quote \
+ quotearg \
+ readline \
+ readme-release \
+ realloc-posix \
+ relocatable-prog \
+ relocatable-script \
+ rename \
+ snprintf-posix \
+ spawn-pipe \
+ sprintf-posix \
+ stdbool \
+ stpcpy \
+ strdup-posix \
+ strerror \
+ strverscmp \
+ timevar \
+ unistd \
+ unistd-safer \
+ unlink \
+ unlocked-io \
+ unsetenv \
+ update-copyright \
+ verify \
+ vsnprintf-posix \
+ vsprintf-posix \
+ warnings \
+ winsz-ioctl \
+ winsz-termios \
+ xalloc \
+ xalloc-die \
+ xconcat-filename \
+ xhash \
+ xlist \
+ xmemdup0 \
+ xstrndup
+
+build-aux/prefix-gnulib-mk --lib-name=libbison lib/gnulib.mk