* Set `__cpp_auto_cast`, as per
https://github.com/cplusplus/CWG/issues/281
* Support `__has_extension(cxx_generalized_nttp)` in C++20 as the
feature isn't stable enough for a feature test macro
* Support `__has_extension(cxx_explicit_this_parameter)` in c++23 as the
feature isn't stable enough for a feature test macro
Add __has_feature and __has_extension checks for C++1y features (based on the provisional names from
the C++ features study group), and update documentation to match.
llvm-svn: 181342
__has_extension is a function-like macro which takes the same set
of feature identifiers as __has_feature. It evaluates to 1 if the
feature is supported by Clang in the current language (either as a
language extension or a standard language feature) or 0 if not.
At the same time, add support for the C1X feature identifiers
c_generic_selections (renamed from generic_selections) and
c_static_assert, and document them.
Patch by myself and Jean-Daniel Dupas.
llvm-svn: 131308
