Just a heads up for anyone who bumps into this and is scratching their head. If you have ninja version 1.9.0 installed your build may hit an error with messages like this:
ninja: error: build.ninja:4404: multiple rules generate C:/work/westtest/ncs/zephyr/subsys/logging/Kconfig.template.log_config [-w dupbuild=err]
This used to be just a warning in version 1.8.2 but was changed recently.
That'll teach me to be on the bleeding edge.
The short term workarounds are to either pass '-w dupbuild=warn' to ninja as an option, or to downgrade back to 1.8.2.
Cheers!