anchor.diff:  /// [omit]
   let ccBuildLabel = environVar "CCNETLABEL"
   
  +/// AppVeyor build number
  +/// [omit]
  +let appVeyorBuildNumber = environVar "APPVEYOR_BUILD_NUMBER"
  +
   /// The current build server
   let buildServer = 
       if hasBuildParam "jenkins_home" then Jenkins
       elif not (isNullOrEmpty tcBuildNumber) then TeamCity
       elif not (isNullOrEmpty ccBuildLabel) then CCNet
       elif not (isNullOrEmpty travisBuildNumber) then Travis
  +    elif not (isNullOrEmpty appVeyorBuildNumber) then AppVeyor
       else LocalBuild
   
   /// The current build version as detected from the current build server.
  
positive.code:     | CCNet
      | Jenkins
      | Travis
      | LocalBuild
  
  /// The trace mode option.
  
negative.code:     | TeamCity -> getVersion tcBuildNumber
      | CCNet -> getVersion ccBuildLabel
      | Travis -> getVersion travisBuildNumber
      | AppVeyor -> getVersion appVeyorBuildNumber
      | LocalBuild -> getVersion localBuildLabel
  
  /// Is true when the current build is a local build.
  