Summary:
Right now all these libraries are installed in the `libclc/` directory
in the compiler's resource directory. We should instead follow the
per-target approach and install it according to the triple. The
sub-architectures will be put in a subdirectory as well.
I will do refactorings on this later to remove all the redundant targets
and pull this into common handling.
Also we should accept `--libclc-lib` without an argument to just find it
by default. I don't know what the plan here is since AMDGCN is the only
triple that uses this flag.
c5cb48c397