Rename libraries on Mac OS to prevent conflicts.

Rename libraries on Mac OS to prevent conflicts.

ANGLE and SwiftShader produce libraries with the same name, which causes
conflicts for Chrome on Mac OS when creating unstripped libraries and
dSYM debug information. Renaming them temporarily works around the build
tools issue.

Bug chromium:735920

Change-Id: Icb4f484970ec75b8c5e7e784ce37e05ee4fbc7db
Reviewed-on: https://swiftshader-review.googlesource.com/10288
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>