Qt for Mac OS X - Requirements
Qt requires Xcode to be installed on the system. You can get it from:
http://developer.apple.com/xcode/
The command line tools are also needed, they can be installed within XCode:
Xcode->Preferences->Downloads->Components->Command Line Tools
Required Compiler Versions
Qt for Mac OS X is tested and compatible with several versions of GCC (GNU Compiler Collection) and Clang (as available from Xcode). For a list of tested configurations, refer to the Reference Configuration section of the Supported Platforms page.
Mac OS X on PowerPC hardware
Qt 5 does not support OS X on PowerPC.