[clang] [llvm] [mlir] [CMake] Add dependent project mode for Flang's MLIR (PR #221724)

[Mehdi Amini via cfe-commits]

joker-eph wrote:

> > > That said, ergonomically, I think detecting 'we added this because a different project needs it' anything automatically is going to be problematic?
> > 
> > 
> > I don't quite follow, can you expand?
> 
> Sure! My opinion is adding MLIR, automatically or not to `LLVM_ENABLE_PROJECTS` should build the whole thing, 

I was asking really why you said "....  is going to be problematic" though. I still miss the answer on this?
You're presenting a different design and something that is somehow orthogonal maybe, and I actually don't quite see how it solves the problem. Clang and Flang have different dependencies on MLIR for example, and other downstream also would have other needs, so the notion of a "minimal" MLIR wouldn't satisfy anyone.

https://github.com/llvm/llvm-project/pull/221724