Feature Request: Force model recompile in stan() or automate recompile if saved dso is from a different platform

Summary:

It would be helpful to have an argument in stan() to force a model recompile, or for stan() to automatically recompile if it discovers that the saved dso was compiled on a different platform

Description:

When collaborating with colleagues using different platforms, or when one uses a mix of platforms oneself, stan() will fail because the saved dso was compiled on the wrong platform. There is no obvious way to write code to find and remove the compiled model and there is no setting in stan() to force a recompile. Seemingly the only way to force a recompile within R is to trivially modify the model code (eg adding a white space). There should be an argument for this in the relevant rstan functions so that it is possible to write code that works reliably when used by multiple researchers accessing the same scripts via a syncing service (eg Dropbox) as this is a very common use case.

The requested entry point is stan() in the RStan interface; start by tracing how it reuses saved DSOs and how platform mismatches are surfaced. Define whether an explicit force-recompile argument or automatic platform check is intended, then verify that shared scripts recompile safely across platforms.