I will do that. I will update my own Launcher due to a feature request, and then I will look into compiling your Launcher with Qt and performing necessary changes (if any). I will post back when I do this.
There will be for sure, cause the non-portable code is separated in arch by dirs. And OSX one is empty. I'll prepare some teplate for you (function declarations, project file, etc).
EDIT: Done, qmake project file "should" be ok. For the source look into src/macx dir. For an example of what to expect look into src/win, src/unix.
Functions you'd need to implement:
// returns dir where game executable and "data" dir exist (here's the problem as I dont know whether fs2 data is bundled in .app in OSX or not, never seen it in my life. if it is bundled then this will require some redesign
QString FilePaths::getGameDir()
// returns config dir (f.e. ~/.fs2_open on linux)
QString FilePaths::getConfigDir()
// returns any writeable dir (flags.lch will be written to it)
QString FilePaths::getTempDir()
// runs the command with parameters and eventually waits for the command to finish
bool System::run(const QString &exec, const QStringList ¶ms, bool waitForEnd)
// self explanatory
bool System::runBrowser(const QString &url)
// miliseconds sleep
int System::mSleep(int msec)
// i think you can leave the following as it is
QSize System::getSize()