We now require a compiler with C++17 support, so we don't need to check for features added to GCC 5 or Clang 3.2. Clang builtin availability checks were unused anyway as Clang defines `__GNUC__` as it's also a GNU C implementation. Fixes #36986.
We now require a compiler with C++17 support, so we don't need to check for features added to GCC 5 or Clang 3.2. Clang builtin availability checks were unused anyway as Clang defines `__GNUC__` as it's also a GNU C implementation. Fixes #36986.