[llvm] [Offload] Remove unnecessary omp CMake target dependencies (PR #149060)

[Kenneth Benzie via llvm-commits]

kbenzie wrote:

Is https://github.com/llvm/llvm-project/pull/136729 related to that?

I'm wondering if it would it be possible to move the implementations of these libomp entry points into libomptarget and have libomp be implemented in tersm of libomptarget rather than this circular dependency situation?

https://github.com/llvm/llvm-project/pull/149060