kmod driver incompatibilities with 11.1R created packages used on 11.2R

[Dave Cottlehuber]

We've probably all seen the problems that non-developer users have run into with the various packages that have a dependency on kernel versions, when using the official pkg.freebsd.org built versions.

We know that the problem will go away as soon as 11.1R is EOL end September, but in the interim I can imagine this must be really frustrating for people who don't have a familiarity with building from sources. Is there anything we can do to help them? they're often newcomers to FreeBSD so their new user experience is crap.

Here's a few ideas, but there may be better ones:

- put a note in pkg-message informing users of the issue and a link to a forums.freebsd.org post on how to build it manually
- add something to the port's pkg-install script to only display that message on < 11.2R kernels
- provide an alternative pkg repo so they don't have to build from source (possibly community supported) 

I'm specifically thinking of x11/nvidia-driver here but there are presumably other packages impacted from https://www.freshports.org/kld/

https://www.freebsd.org/security/security.html#sup

A+
Dave