VCForPython27.msi安装后， 还显示error: Unable to find vcvarsall.bat

C:\Users\zpc\AppData\Local\Programs\Common\Microsoft\Visual C++ for Python\9.0\VC

增加环境变量：

SET VS90COMNTOOLS=C:\Users\zpc\AppData\Local\Programs\Common\Microsoft\Visual C++ for Python\9.0\VC\bin

if toolsdir and os.path.isdir(toolsdir):
            productdir = os.path.join(toolsdir, os.pardir, os.pardir, "VC")

if toolsdir and os.path.isdir(toolsdir):
            productdir = os.path.join(toolsdir, os.pardir, os.pardir)