[llvm] [OFFLOAD] Add support for host offloading device (PR #177307)

[Alex Duran via llvm-commits]

adurang wrote:

> This broke our bot: https://lab.llvm.org/buildbot/#/builders/10/builds/22566 It was red before because of a failing test. This one broke the build. From the log
> 
> ```
> -- Building x86_64 plugin linked with libffi
> CMake Error at /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.src/offload/plugins-nextgen/CMakeLists.txt:54 (add_subdirectory):
>   The binary directory
>     /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.build/runtimes/runtimes-bins/offload/plugins-nextgen/host
>   is already used to build a source directory.  It cannot be used to build
>   source directory
>     /home/botworker/builds/openmp-offload-amdgpu-runtime-2/llvm.src/offload/plugins-nextgen/host
>   Specify a unique binary directory name.
> -- Building the llvm-offload-device-info tool
> ```
> 
> Is this an issue with the bot config or this PR?
> 
> Edit: I checked across the rest of our fleet. This appears to be local to this bot. Let me do an investigation.

issue should be fixed by #181346

https://github.com/llvm/llvm-project/pull/177307