[patch] libstdc++/60637 Fix C++98 std::signbit<long double>

[Marc Glisse]

On Mon, 18 Jan 2016, Jonathan Wakely wrote:

> This fixes PR60637 by using the appropriate built-in for the size of
> the argument type. In Bugzilla Marc asked why we don't just use the
> same code as for C++11, but I want to make this less intrusive change
> on the branches (trunk is already OK anyway).

That's fine for the branch indeed, but I don't see why we couldn't remove 
that illegal signbit declaration on trunk in C++98 mode. It works but it 
is still wrong to have it. Now that C++14 is the default, explicitly 
asking for C++98 looks like a clear sign to me that people don't want such 
extensions.

-- 
Marc Glisse