blktap-dkms 2.0.93-0.7ubuntu2~16.04.1: blktap kernel module failed to build [error: implicit declaration of function ‘copy_to_user’]

[rjasmin]

upstream bug preventing libvirt and its depends from using virtual network devices. This fails on buster, but is ok on stretch- somewhere downwind of ubu16 we are ok.

its the kernel link to the dkms files that is broken. somewhat easy fix.
similar to vbox problems from time to time.

libvirt and qemu-kvm are the way to go- when it works.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: blktap-dkms 2.0.93-0.7ubuntu2~16.04.1
ProcVersionSignature: Ubuntu 4.15.0-37.40~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-37-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
DKMSKernelVersion: 4.15.0-37-generic
Date: Sun Oct 7 18:02:12 2018
DuplicateSignature: dkms:blktap-dkms:2.0.93-0.7ubuntu2~16.04.1:/var/lib/dkms/blktap/2.0.93/build/control.c:165:7: error: implicit declaration of function ‘copy_to_user’ [-Werror=implicit-function-declaration]
InstallationDate: Installed on 2018-10-07 (0 days ago)
InstallationMedia: Ubuntu-MATE 16.04.4 LTS "Xenial Xerus" - Release amd64 (20180228)
PackageVersion: 2.0.93-0.7ubuntu2~16.04.1
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.4
 apt 1.2.28
SourcePackage: blktap-dkms
Title: blktap-dkms 2.0.93-0.7ubuntu2~16.04.1: blktap kernel module failed to build
UpgradeStatus: No upgrade log present (probably fresh install)