Fix MacOSX Urho3D shared library build when LuaJIT is enabled.

Also fix Urho3D.pc for MacOSX platform to also provide the framework list required for linking, i.e. below command works equally well with Urho3D SDK installed on Mac OS X platform.
c++ -o Urho3DPlayer Urho3DPlayer.cpp `pkg-config --cflags --libs Urho3D`