Introduce LINUXKPI_GENSRCS.

[kib]

Summary

Centralize the list of generated files required by linuxkpi consumers, into the common variable. This way, consumers that use the variable are insulated from possible changes in the list.

I did not tried to save some optional dependencies. I probably should also move opt_inet.h and opt_inet6.h there, but lets see how this approach pass the review.

[• hselasky]

Looks good. I have no problem with this.

[imp]

This looks good, and should be merged to stable/12 and stable/11. We'll work to put this workaround in the kms-drm stuff, and others will need to do the same if they haven't already (there's at least one effort to update the kms-drm stuff that this broke).
Once all that's been done end-to-end, we can back out the workaround I put in to avoid the problem.