GCC style fallthrough attribute is used with clang versions that don't support it #128902
Description
Bug report
Bug description:
Include/pyport.h currently only guards use of __attribute__((fallthrough)) with _Py__has_attribute(fallthrough). Clang versions prior to 10 do not support this syntax, but do claim to support the fallthrough attribute (because they support the C++11 style [[fallthrough]]).
CPython versions tested on:
3.14
Operating systems tested on:
macOS