1. Xcode 4.4 and MacOSX SDK 10.6 on Lion.

    In XCode 4.4 Apple has made the decision to not ship the MacOSX10.6.sdk that is in use by 100s of apps. The choice is to either not install XCode 4.4 and continue using XCode 4.3 or if you have already downloaded XCode 4.4 you need to get the XCode 4.3 DMG from Apple and then extract the MacOSX10.6.sdk from it and place it with the other SDK versions.

    If you already have a /Developer/SDKs/MacOSX10.6.sdk SDK bundle, then its possible to symlink it in and skip these instructions.

    1. Go to Apple Developers download page and download XCode 4.3.3 for Lion.
    2. Mount the DMG on the desktop and right(option) click to choose Show Package Contents.
    3. Copy Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.6.sdk Folder
    4. In a terminal or iTerm2 open the SDK folder by typing
    5. open /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs
    6. Paste in the SDK folder with the other SDKs
    7. And continue on building

    Please note that I haven’t tested this on Mountain Lion, so your experience with MacOSX10.6.sdk on that platform might vary.