Build: do not rename app to QtSerialPort; typo fix
Libs: Rebuild libosg for OSX using @rpath

Configure and build using:

cmake -G Ninja -DOSG_USE_QT=OFF -DBUILD_OSG_APPLICATIONS=OFF -DCMAKE_MACOSX_RPATH=ON

This should make the dylibs work, and not have them hardcode my build directory's path into their relative lookup foo.