I\'ve installed xCode 4 last night and tried to compile a software which should support 10.5 and above OSs.
It gave the error message \"Base SDK missing\". I found t
Dropping the 10.5 SDK is also a problem for software which does not use Xcode for the build system, but expects (perhaps foolishly) for specific SDKs to be in place.
To add the SDK back, I re-installed the MacOSX10.5.pkg
from the Xcode 3.2.6 download. It is in a hidden folder named "Packages" on the disk image. After mounting the .dmg file, you can open it from the command line with open /Volumes/Xcode\ and\ iOS\ SDK/Packages/
. When installing the package, choose change install location and option-click on the drive you want to install to, so that you can specify a folder. The target folder should be /Developer
or the base of your Xcode 4 install if you have put it in a non-standard location.
You can copy it from another Xcode installation into the /YourDeveloperFolder/SDKs/...
but Xcode 4 still will not build Universal (Intel/PPC) binaries, essentially making it all but pointless to use the 10.5 SDK (except for "this method doesn't exist yet" style warnings). The official word from Apple (via their devforums): If you need 10.5/PPC support, stick with Xcode 3.