How to reliable detect a MacPorts-ported compiler?

[Jeffrey Walton]

On Mon, Sep 7, 2015 at 5:04 PM, Rainer Müller <raimue at macports.org> wrote:
> On 2015-09-07 02:46, Jeffrey Walton wrote:
>> We have some users reporting issues under MacPort-ported compilers
>> (specifically, Issue 37664, https://trac.macports.org/ticket/37664).
>>
>> How do I reliably detect a MacPorts-ported compiler?
>
> Wouldn't it be more correct to detect gcc on OS X as apparently this
> feature is not supported no matter where the compiler comes from?
>
Thanks.

For Apple, we can detect Apple ported gear with:

  $ clang++ -dM -E - < /dev/null | grep -i apple
  #define __APPLE_CC__ 6000
  #define __APPLE__ 1
  #define __VERSION__ "4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)"
  #define __apple_build_version__ 5030040

What strings or bits is MacPorts providing?

Thanks again.