title: how to set v140_xp toolset in command prompt for build with NMake?
body: <p>I have some lib project that should be built with <code>nmake</code> makefiles for Windows XP. </p>
  
  <p>How to change toolset in VS2015 Native Command Prompt from <code>v140</code> to <code>v140_xp</code> (Visual Studio 2015 - Windows XP (v140_xp)).
  Any ideas ?</p>