scons/windows: Enable compute shaders when possible.

Tests done with llvm-config indicate that there are only 2 libraries in
irreader and not in engine, LLVMAsmParser and LLVMIRReader and both of them
are part of coroutines so I replaced irreader with coroutines and added
libraries unique to coroutines.

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
1 file changed