anchor.diff:    module internal FSharpAssemblyHelper =
         open System.IO
         let checker = FSharpChecker.Create()
  -
  +      
  +      let (++) a b = System.IO.Path.Combine(a,b)
  +      let sysDir =
  +        if System.Environment.OSVersion.Platform = System.PlatformID.Win32NT then
  +          @"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0"
  +        else
  +          System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory()
         let sysLib nm = 
  -          if System.Environment.OSVersion.Platform = System.PlatformID.Win32NT then // file references only valid on Windows 
  -              @"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\" + nm + ".dll"
  -          else
  -              let sysDir = System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory()
  -              let (++) a b = System.IO.Path.Combine(a,b)
  -              sysDir ++ nm + ".dll" 
  +          sysDir ++ nm + ".dll" 
   
         let fsCore4300() = 
             if System.Environment.OSVersion.Platform = System.PlatformID.Win32NT then // file references only valid on Windows 
  
positive.code:                       //yield "--optimize-" 
                        yield "--nooptimizationdata"
                        yield "--noframework"
                        if msCoreLib.IsSome then
                          yield sprintf "-r:%s" msCoreLib.Value
                        if fsCoreLib.IsSome then
                          yield sprintf "-r:%s" fsCoreLib.Value
                        yield "--out:" + dllName
  
negative.code:               sysLib "FSharp.Core"
  
        let getProjectReferences otherFlags libDirs dllFiles = 
            let dllFiles = dllFiles |> Seq.toList
            let hasAssembly asm = dllFiles |> Seq.exists (fun a -> Path.GetFileNameWithoutExtension a = asm)
            let hasFsCoreLib = hasAssembly "FSharp.Core"
            let fsCoreLib =
              if not hasFsCoreLib then Some (fsCore4300())
              else None
            let defaultReferences = [ "mscorlib"; "System"; "System.Core" ]
            let otherFlags = defaultArg otherFlags Seq.empty
            let libDirs = defaultArg libDirs Seq.empty
            let base1 = Path.GetTempFileName()
  