Missing headers

[molcik]

Building DKMS modules on this kernel fails, because of missing headers.

Folders /lib/modules/KERNEL_V/build and /lib/modules/KERNEL_V/source are symlinked to non existing location /rpi-kernel/linux (this folder exists only in docker environment).

This causes dkms modules to fail.

Solution could be to include make INSTALL_HDR_PATH=/raspios/mnt/disk/usr/src headers_install in build.sh and then symlink the headers. Or copy whole /rpi-kernel/linux, but this would increase image size significantly.