[llvm] [Liboffload] Add function for checking ELF file device compatibility (PR #156259)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> > ELF is too specific, just make it an image and let the runtime check if it's LLVM-IR, PTX, ELF, SPIR-V, whatever.
> 
> Thanks for your feedback! How would you do that since my goal here is to call the `isELFCompatible` function of the device plugin?

Use the same type of entry point `libomptarget` uses. We only support LLVM-IR and ELF right now, but that will likely be expanded in the future. Though, a part of me is wondering if we even need this. We already have a load image function. Couldn't people just try to load the image and check the error? I guess this is necessary in cases where people would want to know if an image can run on a device, but not actually load it if it is.

https://github.com/llvm/llvm-project/pull/156259