anchor.diff:  #endif
             yield! libDirs
             yield System.IO.Directory.GetCurrentDirectory()
  -#if !NETSTANDARD1_5
  +#if !NETSTANDARD
             // Prefer the currently loaded version
             yield fsCore "4.0" loadedFsCoreVersion
             yield fsCore4400Dir
  
positive.code:                //yield "--optimize-"
                 yield "--nooptimizationdata"
                 yield "--noframework"
  #if !NETSTANDARD1_5
                 yield sprintf "-I:%s" (referenceAssemblyDirectory frameworkVersion)
                 for ref in defaultReferences do
                   yield sprintf "-r:%s" (referenceAssembly frameworkVersion ref)
  
negative.code:               Some (findFSCore dllFiles libDirs)
              else None
              
  #if !NETSTANDARD
            let defaultReferences =
              getDefaultSystemReferences frameworkVersion
              |> Seq.filter (not << hasAssembly)
  