Building clang/cling 3.5 for ROOT on Lion

[Ryan Schmidt]

On Apr 8, 2014, at 03:12, Chris Jones wrote:

>>> Indeed. They aren't quite the same thing though in the end, as on OSX 10.8 and newer it supports c++11, whereas on 10.7 it doesn't, because of the underlying system support. So the same clang34 compiler now builds root6 fine on OSX10.9, but fails on 10.7.
>>> 
>>> My recollection of all the previous times c++11 has been discussed, can be summarised as there is no obvious way to support it cleanly on older OSX releases. So if an upstream package, as ROOT6 has, is actively only targetting c++11 supporting compilers, then effectively these ports cannot be used on older OSX releases now. Is that correct, or am I being overly pessimistic here ?
>> 
>> Using latest gcc (currently gcc48) might be a way to support C++11 on OS X < 10.9, but otherwise, with clang, C++11 requires 10.9+.
> 
> Yes, I thought of that. But as I understanding it mixing libc++ and libstdc++ runtimes is an absolute no no when c++11 is involved, so the user would have to update their MacPorts settings to build *everything* with gcc(48) ?

The point is you wouldn’t be mixing C++ runtimes. On 10.8 and earlier, the C++ runtime is libstdc++, just as gcc48’s is. They’re different versions of libstdc++, but sometimes they’re similar enough to still work together.