Normally I get v4l2loopback by simply
git clone https://github.com/umlaeute/v4l2loopback cd v4l2loopback make && sudo make install sudo modprobe v4l2loopback video_nr=10,11
and now I get:
modprobe: FATAL: Module v4l2loopback not found.
It seems to be a problem with the kernel headers. After looking online, no one had a fix just lots of suggestions that don't work or v4l2loopback support saying it's a raspbian issue.
$ uname -a
Linux raspberrypi 4.9.41-v7+ #1023 SMP Tue Aug 8 16:00:15 BST 2017 armv7l GNU/Linux
How do I get v4l2loopback working on raspbian Jessie?