build: add convenience script to set version in configure.in

build/set-fs-version.sh

+#!/bin/sh
+##### -*- mode:shell-script; indent-tabs-mode:nil; sh-basic-offset:2 -*-
+
+sdir="."
+[ -n "${0%/*}" ] && sdir="${0%/*}"
+. $sdir/../scripts/ci/common.sh
+
+check_pwd
+check_input_ver_build $@
+in_ver="$1"
+if [ "$in_ver" = "auto" ]; then
+  in_ver="$(cat build/next-release.txt)"
+fi
+eval $(parse_version "$in_ver")
+set_fs_ver "$gver" "$gmajor" "$gminor" "$gmicro" "$grev"
+