Macports Clang 3.9 compilation failures due to missing <atomic> include

[Chris Jones]

Hi Ken,

Thanks for your useful comments. I am sure you are right and I can clean things up a bit. See as the portfile is now committed and working, I’ll put this on the todo list for when i next update the port due to a version update... Its great to have this available, with it I have been able to get back support for OSX10.7 upwards with it...

Cheers chris

> On 28 Sep 2017, at 7:31 pm, Ken Cunningham <ken.cunningham.webuse at gmail.com> wrote:
> 
> Hi Chris,
> 
> Looking over the xrootd commit, and to hopefully make your life much easier when using the PortGroup cxx11 1.1, you generally don't need to do much of anything beyond adding the PortGroup. You can pretty much expect to delete all the other compiler selection components in your Portfile.
> 
> 
> all the compiler selection issues are handled by the PortGroup. The +libstdcxx variant is automatic with clang-4.0.
> 
> The only thing you might possibly need to adjust is default clang blacklist is <500, so if you need something newer when using libc++, you'd have to spec that. That is unusual.
> 
> Also, I'd hope that we don't blacklist *gcc* any more -- it doesn't add anything when using the cxx11 1.1 PortGroup, and it messes up the PPC fixes (small group, but what the heck).
> 
> Best, 
> 
> Ken
> 
> 
>> On 2017-09-28, at 8:20 AM, Mojca Miklavec wrote:
>> 
>>> On 28 September 2017 at 17:05, Chris Jones wrote:
>>> 
>>>> You need the variant +libstdcxx and clang-4.0 has that one enabled by
>>>> default, while 3.9 doesn't.
>>> 
>>> OK thanks. One of the ports I am interested in fixing will not compile with
>>> clang 4.0 though. Is there a why to do this with 3.9 as well ?
>> 
>> Sure. You need to install clang 3.9 with that variant, but that will
>> take some additional CPU cycles unless we make that option default.
>> 
>> See:
>>   https://trac.macports.org/ticket/54766
>> and probably some other tickets (I can try to dig them out).
>> 
>> If we get rid of some dependencies, it would be easier to justify
>> enabling the option by default on older compilers.
>> 
>> Mojca
>