Merge topic 'ninja-always-make-object-dirs'

de3dc16b64 cmNinjaTargetGenerator: use `.` for the needed phony order-only dependency
1aa28f3b92 cmNinjaTargetGenerator: ensure that the object output directory exists
4a9613ff9b cmNinjaTargetGenerator: add a method to compute the object directory

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !9105