Build libchrome shared library on Mac host

This allows Fluoride (but maybe other Brillo components in future)
unit tests, host-side test tools, and components needed for tasks
such as Bluetooth Qualification to be built on a Mac workstation.

BUG=22771504

Change-Id: I65a0329b26931d8ab48eda4d25cb2ee83278f933
1 file changed