Introduce MODULES_EXCLUDE

[manu]

Summary

It's sometimes easier to exclude some modules rather than listing all
possibly needed ones with MODULES_OVERRIDE.
So for this add MODULES_EXCLUDE which do exactly as one would guess, excludes
some modules from the build/install.

For example if one wants to exclude all modules which are only present in the
GENERIC config on amd64 :
export MODULES_EXCLUDE=$(grep -E '^device' sys/amd64/conf/GENERIC | awk '{print $2}' | tr '\n' ' ')

MFC after: 2 weeks
Sponsored by: Beckhoff Automation GmbH & Co. KG

[pauamma_gundo.com]

share/man/man5/make.conf.5

275–277

What happens if both MODULES_EXCLUDE and MODULES_OVERRIDE are present?

[imp]

Love the idea

share/mk/bsd.kmod.mk

6

Don't you need at least a 'clean' target too? What about 'depend'?

[manu]

share/man/man5/make.conf.5

275–277

I'll test but pretty sure that MODULES_EXCLUDE takes precedence (and I think should).
But I'll update the manpage with more info once I've tested

share/mk/bsd.kmod.mk

6

That's all the targets I needed but only test make buildkernel with and without WITHOUT_CLEAN=y

[pauamma_gundo.com]

Given https://reviews.freebsd.org/D33443#inline-206871, and if erroring out or a "both present, ignoring MODULES_OVERRIDE" warning if both are present is an option, I think that would provide better UX. But either way, documenting the behavior as well is good..

[manu]

share/man/man5/make.conf.5

275–277

I meant to say that MODULES_OVERRIDE takes precedence and this is the case.