clang-format.bash: update to clang-format-6.0

Update `.clang-format` with configuration to make the 6.0 format as
close as possible to what 3.8 produced before.  Then revise the style:

* Indent preprocessor directives (a feature new since 3.8)
* Add a newline and indentation before inheritance `:` and `,`

Rename the Git attribute identifying the format to include the
clang-format version number: `format.clang-format-6.0`.  This will aid
external infrastructure in knowing what version of the tool to run.

.clang-format

@@ -1,8 +1,21 @@
 ---
-# This configuration requires clang-format version 3.8 exactly.
+# This configuration requires clang-format version 6.0 exactly.
 BasedOnStyle: Mozilla
 AlignOperands: false
-AlwaysBreakAfterReturnType: None
+AllowShortFunctionsOnASingleLine: InlineOnly
 AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+BinPackArguments: true
+BinPackParameters: true
+BraceWrapping:
+  AfterClass:      true
+  AfterEnum:       true
+  AfterFunction:   true
+  AfterStruct:     true
+  AfterUnion:      true
+BreakBeforeBraces: Custom
 ColumnLimit: 79
+IndentPPDirectives: AfterHash
+SortUsingDeclarations: false
+SpaceAfterTemplateKeyword: true
 ...

.gitattributes

@@ -2,11 +2,11 @@
 .hooks*          export-ignore
 
 # Custom attribute to mark sources as using our C code style.
-[attr]our-c-style  whitespace=tab-in-indent  format.clang-format
+[attr]our-c-style  whitespace=tab-in-indent  format.clang-format-6.0
 
 # Custom attribute to mark sources as generated.
 # Do not perform whitespace checks.  Do not format.
-[attr]generated  whitespace=-tab-in-indent,-indent-with-non-tab -format.clang-format
+[attr]generated  whitespace=-tab-in-indent,-indent-with-non-tab -format.clang-format-6.0
 
 bootstrap        eol=lf
 configure        eol=lf

Help/dev/source.rst

@@ -9,7 +9,7 @@ See documentation on `CMake Development`_ for more information.
 C++ Code Style
 ==============
 
-We use `clang-format`_ version **3.8** to define our style for C++ code in
+We use `clang-format`_ version **6.0** to define our style for C++ code in
 the CMake source tree.  See the `.clang-format`_ configuration file for our
 style settings.  Use the `Utilities/Scripts/clang-format.bash`_ script to
 format source code.  It automatically runs ``clang-format`` on the set of

Source/.gitattributes

@@ -1,2 +1,2 @@
 # Do not format third-party sources.
-/kwsys/**                                  -format.clang-format
+/kwsys/**                                  -format.clang-format-6.0

Source/CursesDialog/form/.gitattributes

@@ -1 +1 @@
-* -format.clang-format
+* -format.clang-format-6.0

Tests/CSharpLinkFromCxx/.gitattributes

@@ -1 +1 @@
-UsefulManagedCppClass.* -format.clang-format
+UsefulManagedCppClass.* -format.clang-format-6.0

Tests/CompileFeatures/.gitattributes

@@ -1,2 +1,2 @@
 # Do not format a source containing C++11 '>>' syntax as C++98.
-cxx_right_angle_brackets.cpp -format.clang-format
+cxx_right_angle_brackets.cpp -format.clang-format-6.0

Tests/PositionIndependentTargets/.gitattributes

@@ -1,2 +1,2 @@
 # Do not format a source where we want a long line preserved.
-pic_test.h -format.clang-format
+pic_test.h -format.clang-format-6.0

Tests/RunCMake/CommandLine/cmake_depends/.gitattributes

@@ -1,2 +1,2 @@
 # Do not format a source encoded in UTF-16.
-test_UTF-16LE.h -format.clang-format
+test_UTF-16LE.h -format.clang-format-6.0

Tests/RunCMake/GenerateExportHeader/reference/.gitattributes

@@ -1,2 +1,2 @@
 # Exclude reference content from formatting.
-* -format.clang-format
+* -format.clang-format-6.0

Tests/VSWinStorePhone/Direct3DApp1/.gitattributes

@@ -1 +1 @@
-Direct3DApp1.cpp -format.clang-format
+Direct3DApp1.cpp -format.clang-format-6.0

Utilities/.gitattributes

@@ -3,5 +3,5 @@
 SetupForDevelopment.sh  export-ignore
 
 # Do not format third-party sources.
-/KWIML/**       -format.clang-format
-/cm*/**         -format.clang-format
+/KWIML/**       -format.clang-format-6.0
+/cm*/**         -format.clang-format-6.0

Utilities/Scripts/clang-format.bash

@@ -78,7 +78,7 @@ test "$#" = 0 || die "$usage"
 
 # Find a default tool.
 tools='
-  clang-format-3.8
+  clang-format-6.0
   clang-format
 '
 if test "x$clang_format" = "x"; then
@@ -96,8 +96,8 @@ if ! type -p "$clang_format" >/dev/null; then
     exit 1
 fi
 
-if ! "$clang_format" --version | grep 'clang-format version 3\.8' >/dev/null 2>/dev/null; then
-    echo "clang-format version 3.8 is required (exactly)"
+if ! "$clang_format" --version | grep 'clang-format version 6\.0' >/dev/null 2>/dev/null; then
+    echo "clang-format version 6.0 is required (exactly)"
     exit 1
 fi
 
@@ -115,8 +115,8 @@ esac
 $git_ls |
 
   # Select sources with our attribute.
-  git check-attr --stdin format.clang-format |
-  grep -e ': format\.clang-format: set$'     |
+  git check-attr --stdin format.clang-format-6.0 |
+  grep -e ': format\.clang-format-6\.0: set$'     |
   sed -n 's/:[^:]*:[^:]*$//p'                |
 
   # Update sources in-place.