Feature request: an API to register externally defined tapir target

[tkf]

This is a feature request/question on the API for using externally defined tapir target. IIUC, opencilk does not have an API for this. Can we have, for example, a method

using TapirTargetFactory = std::function<TapirTarget *(Module &)>;
TargetLibraryInfoImpl::setTapirTarget(TapirTargetFactory target)

where targetis a function that takes a module and return a target? This is how I actually use it.

I'm not suggesting this particular API and this PR is just to concretely illustrate what functionality I'd like to access. Also, this implementation is terrible and have to be written in such a way that you don't need to use a global variable (This patch is optimized for minimal diff ATM). If this API is OK to add, I can try moving the state into TargetLibraryInfoImpl.