anchor.diff:  | TeamCity
   | CCNet
   | Jenkins
  +| Travis
   | LocalBuild
   
   /// The trace mode option.
  
positive.code:     | Jenkins ->    getVersion jenkinsBuildNumber
      | TeamCity ->   getVersion tcBuildNumber
      | CCNet ->      getVersion ccBuildLabel
      | LocalBuild -> getVersion localBuildLabel
  
  /// Is true when the current build is a local build.
  
negative.code: /// [omit]
  let tcBuildNumber = environVar "BUILD_NUMBER"
  
  /// Build number retrieved from Travis
  /// [omit]
  let travisBuildNumber = environVar "TRAVIS_BUILD_NUMBER"
  
  /// Build number retrieved from Jenkins
  /// [omit]
  let jenkinsBuildNumber = tcBuildNumber
  