Fix build on older Macs with universal binary Clang

Our Clang is not built to handle old linkers by default, so if we do not
configure this explicitly it may attempt to use flags that are not
supported by the version of the Darwin linker installed on the build
machine.

Bug: 191276541
Test: build rs on 10.13
Change-Id: Ia40170b6aeba11fb6997021ec3f73e911e0b057c