Setting the Path and Environment Variables for Command-Line Builds
にある通り，vcvarsall.bat をたたけばいいらしい．
@echo off set PATH=C:\LLVM\bin;%PATH% "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64
Setting the Path and Environment Variables for Command-Line Builds
にある通り，vcvarsall.bat をたたけばいいらしい．
@echo off set PATH=C:\LLVM\bin;%PATH% "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64