Make miss dependencies when add_custom_command depends on add_custom_target or add_custom_command

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this is probably the same than the add_depenencies() issue multiple users come across.
(e.g. How to create file-dependency for all sources of target?)
While this is documented, i think this is something that should be globally fixed maybe via a policy setting.
IMO: When A depends on a target B, you always want both:

  1. A is built after B
  2. A needs rebuild if B needs rebuild.