For those who want to use an RTL dongle with their Mac as an SDR, but don't want to go through the hassle of installing the rtl libraries, I've created a server app, CocoaRTLServer 2.0. This is an update that does away with the need to install anything else. Just run this app, then run SdrDx, Cocoa1090, etc.
This app emulates two kinds of SDR servers. First, it acts like rtl_tcp, so it can be used with Cocoa1090 and similar apps. Second, it follows the RF Space protocol, so it can be used with SdrDx.
CocoaRTLServer is entirely free, and can be downloaded here:
http://www.blackcatsystems.com/software/cocoa_rtl_server.htmlIt should work with Mac OS X 10.6 through 10.11.
Some major updates to SdrDx are in the works, adding Wide FM support, including RDS and SCA decoding. These are in the latest beta of SdrDx now.