[llvm] [OpenMP] Add support for custom callback in AMDGPUStream (PR #112785)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> Can you stack the PRs such that we can have a clear idea of what you are trying to do?

Stacking PRs in GH is a pain, and I haven't finished the other part yet. I thought that this was straightforward enough to show that it doesn't break anything with the promise that it will have a user later.

https://github.com/llvm/llvm-project/pull/112785