To build on Mac OS X (10.5 or later):1) Install http://www.libsdl.org/release/SDL-1.2.14.dmg2) Install Qt 4.6.2 with Cocoa http://get.qt.nokia.com/qt/source/qt-mac-cocoa-opensource-4.6.2.dmg3) Run qmake4) Run "xcodebuild -configuration Release" or open "opengroundcontrol.xcodeproj" in Xcode and build.