Add a script to run clang-format on the entire source tree

List all sources in version control and filter out those that we should
not format for various reasons.  Then run the clang-format tool to do an
in-place update.

Utilities/Scripts/clang-format.bash

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+#=============================================================================
+# Copyright 2015-2016 Kitware, Inc.
+#
+# 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.
+#=============================================================================
+
+usage='usage: clang-format.bash [<options>] [--]
+
+    --clang-format <tool>              Use given clang-format tool.
+'
+
+die() {
+    echo "$@" 1>&2; exit 1
+}
+
+#-----------------------------------------------------------------------------
+
+# Parse command-line arguments.
+clang_format=''
+while test "$#" != 0; do
+    case "$1" in
+    --clang-format) shift; clang_format="$1" ;;
+    --) shift ; break ;;
+    -*) die "$usage" ;;
+    *) break ;;
+    esac
+    shift
+done
+test "$#" = 0 || die "$usage"
+
+# Find a default tool.
+tools='
+  clang-format
+  clang-format-3.8
+'
+if test "x$clang_format" = "x"; then
+    for tool in $tools; do
+        if type -p "$tool" >/dev/null; then
+            clang_format="$tool"
+            break
+        fi
+    done
+fi
+
+# Verify that we have a tool.
+if ! type -p "$clang_format" >/dev/null; then
+    echo "Unable to locate '$clang_format'"
+    exit 1
+fi
+
+# Filter sources to which our style should apply.
+git ls-files -z -- '*.c' '*.cc' '*.cpp' '*.cxx' '*.h' '*.hh' '*.hpp' '*.hxx' |
+
+  # Exclude lexer/parser generator input and output.
+  egrep -z -v '^Source/cmCommandArgumentLexer\.' |
+  egrep -z -v '^Source/cmCommandArgumentParser(\.y|\.cxx|Tokens\.h)' |
+  egrep -z -v '^Source/cmDependsJavaLexer\.' |
+  egrep -z -v '^Source/cmDependsJavaParser(\.y|\.cxx|Tokens\.h)' |
+  egrep -z -v '^Source/cmExprLexer\.' |
+  egrep -z -v '^Source/cmExprParser(\.y|\.cxx|Tokens\.h)' |
+  egrep -z -v '^Source/cmFortranLexer\.' |
+  egrep -z -v '^Source/cmFortranParser(\.y|\.cxx|Tokens\.h)' |
+  egrep -z -v '^Source/cmListFileLexer(\.in\.l|\.c)' |
+
+  # Exclude third-party sources.
+  egrep -z -v '^Source/(cm_sha2|bindexplib)' |
+  egrep -z -v '^Source/(kwsys|CursesDialog/form)/' |
+  egrep -z -v '^Utilities/(KW|cm).*/' |
+
+  # Exclude reference content.
+  egrep -z -v '^Tests/Module/GenerateExportHeader/reference/' |
+
+  # Exclude manually-formatted sources (e.g. with long lines).
+  egrep -z -v '^Tests/PositionIndependentTargets/pic_test.h' |
+
+  # Exclude sources with encoding not suported by clang-format.
+  egrep -z -v '^Tests/RunCMake/CommandLine/cmake_depends/test_UTF-16LE.h' |
+
+  # Update sources in-place.
+  xargs -0 "$clang_format" -i