Mac – How to install older Xcode version from the App Store

Don't accept this answer without vetting it further first, but I think I noticed something during my install.

I think that you don't get any SDKs as part of the XCode 4 install. It was only after I installed XCode 4 and launched it, that the project window showed a download in progress. Clicking it gave me the option of downloading: OSX 10.6 SDK, Legacy OSX SDK, iOS SDK, and something else that I don't remember at the moment. Perhaps extended documentation.

So, the XCode install itself is still very heavy. What with XCode visually, all it's associated applications and libraries, Clang/LLVM/LLDB, profiling tools, and everything.

But, the SDKs themself? I don't think it comes automatically. I can't seem to figure out how to get back to choose the other SDKs to download, so I'm not 100% sure in this.

I think that a package manager will do most of what you need. I will show macports as that is the one I know but the others have similar functionality.

If you use the standard packages ie the up to date ones that have been packaged then macports will do all the dependencies for you. e.g. building scipy knows it has to build numpy first and will do it. You can also ninstall a port easily - macports will tell you if any ports depend on it. If a port is chnaged then macports will update the ports depending on it.

You can also manually chnage the port to deal with development versions of numpy for example. You will have to produce a copy of the port file and edit that see macports guide. The minimum would be to change the version and the rules for downloading so you get different code but can include many patches for OSX specific functions.

You can keep track of what you have installed by port list (also more advanced calls to minimise the number of commands you need. The changes you made will be in your local Portfile repository which will need to be backed up and a small change to the defualt macports config made.