求教如何编译clang

[ErrorErro]

SVN check out的 llvm 3.3和clang

先编译llvm
用CMake生成MinGW的Makefile，先是报错找不到Python，安装之后又提示

CMake Error at CMakeLists.txt:308 (message):
  Unexpected failure executing llvm-build: Traceback (most recent call last):

    File "E:/DeveloperTools/llvm_build/llvm-3.3.src/utils/llvm-build/llvm-build", line 3, in <module>
      import llvmbuild
    File "E:\DeveloperTools\llvm_build\llvm-3.3.src\utils\llvm-build\llvmbuild\__init__.py", line 1, in <module>
      from main import main

  ImportError: No module named 'main'

我记得不需要Python啊，是CMake参数设置的不对吗，用的都是默认
试了一下生成Visual Studio12，同上出错
求解