[PATCH] Fix building gdb with gcc-4.x

[Luis Machado]

Hi Bernd,

On 1/4/21 5:57 PM, Bernd Edlinger wrote:
> Hi,
> 
> with Luis' commit of today the trunk is no longer able to
> be compiled with gcc-4.x.
> 
> The problem is std::is_trivially_default_constructible is
> not defined before gcc-5 although the compiler supports C++11
> 

Sorry for the breakage. It looks like GCC 4.x does not fully support 
C++11, although it used to be able to build GDB.

> I am not sure about what's the best approach for conditionally
> enabling the code, especially for compilers other than g++.

Right now it looks like GDB's requirement is a compiler that (fully?) 
supports C++ 11. It doesn't seem to name specific minimum versions of 
compilers.

With that said, I wouldn't mind a conditional in the code to support 
builds with GCC 4.x, if that is deemed important. But as we start using 
more and more C++ 11 constructs, breakages may happen again in the future.

> 
> 
> This fixes the build for me.
> Is it OK for trunk?
> 
> 
> Thanks
> Bernd.
>