How can I install the OSX 10.4u SDK to support backwards compatible OSX builds?

XCode 4 doesn't install 10.4u开发者_如何学Python SDK but some builds require it. How can I get and install it?

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Apparently, Apple dropped 10.4 when releasing Xcode 4 (see Xcode4 with Mac OS X 10.4 SDK).

There is a workaround documented here:
How can we restore ppc/ppc64 as well as full 10.4/10.5 SDK support to Xcode 4?

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Phracker has compiled all the old SDKs from 10.1.5 to 10.11 on Github. https://github.com/phracker/MacOSX-SDKs