[script] add a script to make source pretty (#4167)

This commit adds a script to make source pretty in a temporary
directory.

script/make-pretty

@@ -0,0 +1,58 @@
+#!/bin/bash
+#
+#  Copyright (c) 2019, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+set -e -x -o pipefail
+
+readonly TMP_DIR="/tmp/ot-make-pretty-$(date +%Y%m%d%H%M%S)"
+readonly SRC_DIR="$PWD"
+
+at_exit()
+{
+    EXIT_CODE=$?
+
+    [[ ! -d "${TMP_DIR}" ]] || rm -rf "${TMP_DIR}"
+    exit $EXIT_CODE
+}
+
+make_pretty()
+{
+    ./bootstrap
+    mkdir "${TMP_DIR}"
+    cd "${TMP_DIR}"
+    "${SRC_DIR}/configure"
+    make pretty
+}
+
+main()
+{
+    trap at_exit INT TERM EXIT
+    make_pretty
+}
+
+main "$@"