QNX build without qcc

Does anyone have any experience of creating a QNX project without using the proprietary tools chain. I want to build QNX code for an ARM processor, but not be tied to Momentics.
Although Momentics appears to use standard (GNU) components (make, compiler, linker), it also uses some form of wrapper around them (qcc). Ideally I’d like to simply use gcc, but I need to know which settings Momentics is applying to create ARM code. That information appears to be very difficult to unravel.