On Thu, 24 Jun 2021 at 15:34, Jonathan Wakely wrote: > Rather than use the _GLIBCXX_HAS_BUILTIN macro more widely, I'd prefer > to not use it where it isn't needed, as in the attached (untested) > patch.
My rationale for this is that I'd prefer to use standardized features like __has_include and __has_cpp_attribute where possible, instead of adding more and more configure macros. You don't need to look in c++config.h to see how the macro is defined if you just use a standard feature directly. __has_builtin obviously isn't standardized, but as long as it's available on all the compilers we care about (which it is) then the same rationale applies.
