supported cameras as filesystems; while some cameras implement the
USB Mass Storage class and already appear as filesystems (making
this program redundant), many use the Picture Transfer Protocol (PTP)
or some other custom protocol. But as long as the camera is supported
by libgphoto2, it can be mounted as a filesystem using this program.
N.B. This requires revision 1.50 or later of lib/librefuse/refuse.c
on NetBSD
