build: add script to check for clang-format

Author: kgryte

tools/scripts/check_clang_format

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+#
+# @license Apache-2.0
+#
+# Copyright (c) 2014 The Stdlib Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Check whether clang-format is installed.
+#
+# Usage: check_clang_format
+#
+
+# VARIABLES #
+
+# Find clang-format:
+CLANG_FORMAT=$(command -v clang-format 2>/dev/null)
+
+
+# FUNCTIONS #
+
+# Prints usage information.
+usage() {
+	echo '' >&2
+	echo 'Usage: check_clang_format' >&2
+	echo '' >&2
+}
+
+# MAIN #
+
+if [[ -x "${CLANG_FORMAT}" ]] && "${CLANG_FORMAT}" --version >/dev/null; then
+	echo 'clang-format is installed.' >&2
+	exit 0
+else
+	echo 'ERROR: missing dependency. Please download clang-format version >= 19 (https://clang.llvm.org/; the latest version is recommended). Once installed, run the command again.' >&2
+	exit 1
+fi
+
+# TODO: check for minimum version