Kip branch

[kiplingw]

Patched two compilation errors I experienced with gcc 6.3.0.

[fbb-git]

Hi Kiplingw,

Thanks for your suggestions. I completely agree with your first patch: std:: before thread_local is an error, and it'll be fixed in the next bisonc++ release.
Wrt your 2nd patch i'm not so sure:

• polymorphic semantic values have by now been used quite often, and
  so far no compiler error has been encountered, so I'm wondering what
  might have caused your compiler error.

• You write `required on gcc', but C++ programs are normally compiled
  using g++.

• In the following small piece of code my compiler (neither g++ nor gcc)
  doesn't generate compilation errors:

struct Base
{
    Base();
};
template <int value>
struct Derived
{
    Derived() = default;
    Derived(Derived<value> const &other);
};
template <int value>
Derived<value>::Derived(Derived<value> const &other)
{}
int main()
{
    Derived<5> d5;
    Derived<5> d5b(d5);
}

So, I'm somewhat in the dark as to what may have caused your compiler error.
I used gcc version 6.4.0, and g++ versions 6.4.0 as well as 7.1.0, and none of
these three compilers reported errors.

Until this issue has been resolved, it's probably best not to process your 2nd patch.
Nonetheless, thanks a lot for your suggestions!

F.