[Bug c++/71376] New: __cpp_noexcept_function_type feature test macro not defined.

["eric at efcs dot ca" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71376

            Bug ID: 71376
           Summary: __cpp_noexcept_function_type feature test macro not
                    defined.
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eric at efcs dot ca
  Target Milestone: ---

GCC has recently implemented "noexcept as part of the type system" but the
feature test macro is not defined.

Reproducer:

void foo() noexcept {}

int main() {
    auto fn = &foo;
#if !defined(__cpp_noexcept_function_type)
    static_assert(noexcept(fn()) == false, "");
 #else
    static_assert(noexcept(fn()), "");
#endif
}