[cmake-developers] Suspicious Clang versions

[sean at rogue-research.com]

Yeah, it's confusing... :(

> http://open.cdash.org/testDetails.php?test=201937899&build=2986383
>
> (MacOS 10.7)
>
> The CXX compiler identification is Clang 4.0.0
>
> I do not believe that.

Apple has their own fork/branch of clang which they use in Xcode.  AFAICT
it's not so different from the open source one, it's probably more to do
with them not wanting to tie Xcode's release schedule to clang's.  Anyway,
very confusingly, Apple uses their own version numbering scheme.  So
that's "Apple clang 4.0".  It comes with whatever version of Xcode that
machine's running (4.4 I think?).

> Especially as
>
> http://open.cdash.org/testDetails.php?test=201937829&build=2986379
>
> (MacOS 10.8)
>
> shows 3.4.0. But since even 3.4 does not seem to be released I wonder
> what's
> going on there?

That one is the open source clang, which I build from svn.  It's not from
Xcode.  It's my 'bleeding edge' build machine.  clang is always getting
stricter and getting new warnings, so this help us fix them before a
CMake/VTK/ITK release.

Sean