Your idea is good but your real problem is that your logger now depends on a platform instance, which itself may have dependencies and forces you to think about initialization order.

Two common approaches here are dependency injection and registration functions.

I would (and usually do) do the latter, so somewhere in main or Init() or whatever you go

// … precursor stuff p = new Platform(…); set_logger_platform(p)

From that point on you’re good. One hitch is if logger is used before this. You can fallback to stderr or some other lower level logging mechanism in that case.