Emulation of Linux V4L ioctls

[J.R. Oldroyd]

I have added support for emulation of the Linux V4L video ioctls
in compat/linux/linux_ioctl.[ch].

I am not a committer; the work can be found here:
	http://opal.com/freebsd/sys/compat/linux/
These diffs are made to the 8.0-rc3 sources.

This enables webcam video to work using the linux-skype port
and a pwcbsd-based camera.  I expect it will also allow any other
linux-port to work now, but have only tested with skype.

I have noticed, however, that flash-based webcam apps cause
the npviewer.bin process to hang, so that is not yet working.
Anyone with thoughts on what is going on in the various flash
support layers is welcome to comment on this.

	-jr