I managed to solve a problem that might be something that one of you encounter as well.
I installed a new MBP fetching with migration assistant stuff from a MBAir. On the air, XCode was installed. On the MBP after migration XCode was not available (one of those things Migration Assistant do not migrate properly, as network profile settings, VPN configuration, WLAN configurations and million other non-documented things).
I did installed again using the XCode Installer that was available in /Applications, but that did not solve the problem (i.e. XCode was not installed properly). I then removed XCode Installer, and installed from App Store again. And XCode was now fine. Part from crashing in an unexpected way because “it did not find some iPhone stuff”. I did not care, as I only wanted gcc.
That was yesterday.
Today I was to sync my iPhone, but the phone was not detected by iTunes. Weird…reboot everything, and then check system.log where I found this:
Dec 31 10:54:14 ix com.apple.launchd (com.apple.usbmuxd): posix_spawn("/System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/Resources/usbmuxd", ...): No such file or directory
Some googling did though show me this blog entry.
I.e. an installation of XCode could in some cases ruin your iTunes.
Anyway, now when I knew I had a working XCode Installer, I did run it again, and voila, not only did XCode start without crashing this time, iTunes worked.