After downloaded from github,
run the GenerateProjectFiles.command file,
it says
Setting up Unreal Engine 4 project files...
GenerateProjectFiles ERROR: It looks like youre missing some files that are required in order to generate projects. Please check that youve downloaded and unpacked the engine source code, binaries, content and third-party dependencies before running this script. ~/UDK_4.0/UnrealEngine logout
But I already have Xcode 5.1
and officially they have no reference about third-party dependencies.
any ideas to try?
If you enter the github site again there should be a Getting started page / Readme. You need to follow the links to download the two required files and extract them into the folder where you have the source / command file.