Objective C++ support

[Brad King]

Thiago Macieira wrote:
> As part of the Qt 4.5 update, I'll be pushing the new Phonon backends back to 
> the KDE Subversion server[*]. But the QuickTime 7 backend for the Mac has been 
> completely rewritten in Objective C++ to support QTKit and 64-bit mode 
> (Cocoa).
> 
> There are no .cpp files anymore in phonon/qt7. There are only .mm files.
> 
> What do I need to modify in the buildsystem to support that? Or is it just 
> updating the list of files?
> 
> How about the equivalent to CFLAGS and CXXFLAGS?

CMake currently treats .mm files as C++ sources.  It is up to the C++
compiler to recognize them as Objective C++.

-Brad