Make SwiftShader compile on Mac (with unimplemented functions)

Change-Id: Iaef054314fb27632513397412ca9dc22b67a70ce
Reviewed-on: https://swiftshader-review.googlesource.com/4380
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
6 files changed