It appears that some bundling operations on Mac actually
require that all libraries have a unique name, since
output_dir is effectively ignored and overwritten in that
scenario, so I have to remove that renaming code on Mac so
that SwiftShader doesn't clash with Angle.

Change-Id: I3d36df525ad9229da0c35f27d367e7deef7e430d
Reviewed-on: https://swiftshader-review.googlesource.com/7271Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>