[SOLVED] NSub error on mono when built with vs2012 tools

gistfile1.txt

-- Sorted, see https://gist.github.com/3014681#gistcomment-360816

~/dev/git/mononsub  % gmcs -sdk:4 Program.cs -reference:NSubstitute.dll

Missing method .ctor in assembly /Users/dave/dev/git/mononsub/NSubstitute.dll, type System.Runtime.Versioning.TargetFrameworkAttribute
Can't find custom attr constructor image: /Users/dave/dev/git/mononsub/NSubstitute.dll mtoken: 0x0a00085a

~/dev/git/mononsub  % dmcs Program.cs -reference:newsub40/NSubstitute.dll
Missing method .ctor in assembly /Users/dtchepak/dev/git/mononsub/newsub40/NSubstitute.dll, type System.Runtime.CompilerServices.ExtensionAttribute
Can't find custom attr constructor image: /Users/dtchepak/dev/git/mononsub/newsub40/NSubstitute.dll mtoken: 0x0a000850

-- No error when using NSubstitute.dll built via vs2010 tools. 
-- Only happens with vs2012 tools, and in the DLL targeting net40 (the net35 one works ok).
-- Current nuget/github version is built w/vs2012 (http://nsubstitute.github.com/). 
-- http://bit.ly/nsubbuilds latest is vs2010 tools (login as guest).

-- Program.cs
using System;
using NSubstitute;

public class Program {
    public static void Main() {
        var foo = Substitute.For<IFoo>();
        foo.Foo = "hello";

        Console.WriteLine(foo.Foo);
    }

    public interface IFoo { string Foo { get; set; }}
}

@dsplaisted Thanks!