[libc++] Make sure our .clang-format is used for all languages

[ldionne]

Summary

In particular, this ensures that it is used for Objective-C and
Objective-C++, since we have a few files that get detected as that.

[Mordante]

Thanks! LGTM!

libcxx/.clang-format

69

Can you add a comment here why we don't specify the language.
Just to avoid somebody trying to fix this "omission" in the future.

[ldionne]

Rebase, address comment and reformat __config, which was not being detected as C++ anymore so wasn't getting formatted.

[ldionne]

Update ignore_format.txt

libcxx/.clang-format

 IndentRequires: true
 InsertTrailingCommas: Wrapped
 KeepEmptyLinesAtTheStartOfBlocks: false
 MaxEmptyLinesToKeep: 1
 PackConstructorInitializers: NextLine
 
 PenaltyIndentedWhitespace: 2
 
-Language: Cpp
 Standard: c++20
 SpacesInAngles: Leave
 
 AlwaysBreakTemplateDeclarations: true
 PointerAlignment: Left
 
 
 # libc++'s preferred indentions of preprocessor statements.
 IndentPPDirectives: AfterHash
 
 # libc++ has some long names so we need more than the 80 column limit imposed by LLVM style, for sensible formatting
 ColumnLimit: 120

libcxx/include/__type_traits/is_scalar.h

 #include <__type_traits/integral_constant.h>
 #include <__type_traits/is_arithmetic.h>
 #include <__type_traits/is_enum.h>
 #include <__type_traits/is_member_pointer.h>
 #include <__type_traits/is_null_pointer.h>
 #include <__type_traits/is_pointer.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#pragma GCC system_header
+#  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if __has_builtin(__is_scalar)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> {};
 
-#if _LIBCPP_STD_VER >= 17
-template <class _Tp> inline constexpr bool is_scalar_v = __is_scalar(_Tp);
-#endif
+#  if _LIBCPP_STD_VER >= 17
+template <class _Tp>
+inline constexpr bool is_scalar_v = __is_scalar(_Tp);
+#  endif
 
 #else // __has_builtin(__is_scalar)
 
-template <class _Tp> struct __is_block : false_type {};
-#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
+template <class _Tp>
+struct __is_block : false_type {};
+#  if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
 template <class _Rp, class... _Args>
 struct __is_block<_Rp (^)(_Args...)> : true_type {};
-#endif
+#  endif
 
 // clang-format off
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_scalar
     : public integral_constant<
           bool, is_arithmetic<_Tp>::value ||
                 is_member_pointer<_Tp>::value ||
                 is_pointer<_Tp>::value ||
                 __is_nullptr_t<_Tp>::value ||
                 __is_block<_Tp>::value ||
                 is_enum<_Tp>::value> {};
 // clang-format on
 
 template <>
 struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
 
-#if _LIBCPP_STD_VER >= 17
-template <class _Tp> inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
-#endif
+#  if _LIBCPP_STD_VER >= 17
+template <class _Tp>
+inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
+#  endif
 
 #endif // __has_builtin(__is_scalar)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_SCALAR_H