Fix test-art-target on the Mac.
Fix test-art-target on the Mac.

We only want to avoid using GNU ld options when building host binaries for the
Mac.

Change-Id: I10da9dcbb74ebf68877d16384c962daf40c8d56c

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst