message: Check if using libstdc++ before include <string_view>.
diff: -#if __cplusplus >= 201703L || defined(__has_include) && __has_include(<string_view>)
  +#include <cstddef> // to check __GLIBCXX__
  +#if __cplusplus >= 201703L || (defined(__has_include) && __has_include(<string_view>) && !defined(__GLIBCXX__))
  #include <string_view>
  #else
  #define STX_NAMESPACE_NAME std
  