Description

Offloading to AMD GPUs with GCC currently requires the llvm assembler and linker. binutils should be able to handle that. Implementing the assembler is one thing, and bound to bitrot quickly when AMD isn't vested into it (as they regularly add to the instruction set). The linker is a different thing: once implemented it will remain fairly stable without constant featuritis.

So, implement the BFD backend for amdgcn .o files, so they can be linked with ld.bfd.