anchor.diff:  
   For Visual Studio 2012 and 2013, both x86 and x64 Command Prompt shortcuts
   indicate if they are the "Native Tools" or "Cross Tools" versions. Visual Studio
  -2015 makes the shortcuts even clearer by including the full name of the
  +2015 and 2017 make the shortcuts even clearer by including the full name of the
   architecture.
   
   You cannot at present use a cross-compiler to compile 64-bit OCaml on 32-bit
  
positive.code: 
  for 64-bit. For Visual Studio 2005-2013, you need to use one of the shortcuts in
  the "Visual Studio Tools" program group under the main program group for the
  version of Visual Studio you installed. For Visual Studio 2015, you need to use
  the shortcuts in the "Windows Desktop Command Prompts" group under the
  "Visual Studio Tools" group.
  
  Unlike `SetEnv` for the Windows SDK, the architecture is selected by using a
  different shortcut, rather than by running a command.
  
negative.code: | Visual Studio 2012 | 17.00.x.x    | 32/64-bit               |
  | Visual Studio 2013 | 18.00.x.x    | 32/64-bit               |
  | Visual Studio 2015 | 19.00.x.x    | 32/64-bit               |
  | Visual Studio 2017 | 19.10.x.x    | 32/64-bit               |
  |=====
  
  [[vs1]]
  