Disabling universal on Mojave

[Ryan Schmidt]

On Sep 30, 2018, at 15:07, Jack Howarth wrote:

> Why aren't we leveraging the -DLIBOMP_OSX_ARCHITECTURES cmake flag to control whether "x86_64;i386" or "x86_64" get built?

We already use CMAKE_OSX_ARCHITECTURES, via the cmake portgroup.

The specific problem for libomp was that the portfile was deliberately set to build the universal variant by default.