[Tails-dev] Kernel Headers?

Quick heads up on MacBook 12“ 2015 support:
Was able to successfully build Tails. It works within Parallels.

Now I’m stuck compiling the apple spi drivers. I added a script in config/chroot_local-hooks called 13-1-apple-spi.
I also added the code of its Git repository to config/chroot_local-includes/usr/src/applespi-0.1

Now, the config/chroot_local-hooks/13-1-apple-spi just does:

dkms install -m applespi -v0.1

And I always get the following error during build; how to fix?

DKMS: Add completed.
Error! echo
Your kernel headers for kernel 4.9.0-6-amd64 cannot be found at /lib/modules/4.9.0-6-amd64/build or /lib/modules/4.9.0-6-amd64/source