If you tough you could use any M-mount lens on you Fuji X PRO ! keep in mind that this isn’t true. Some lenses are simply not designed for digital sensors and cans how many unpleasant artifacts (like Corner Color shifting for example). So it is very useful to know that Fuji posted a lens compatibility list you can see here: http://www.fujifilm.com/products/digital_cameras/accessories/lens/mount/fujifilm_m_mount_adapter/compatibility_chart/.
Thanks Fuji for doing this