Build Eto using xbuild

Project "/media/windows/share/Eto/Source/Eto.Direct2D/Eto.Direct2D.csproj" (GetCopyToOutputDirectoryItems target(s)):
                                    Target _ValidateEssentialProperties:
        /usr/lib/mono/4.5/Microsoft.Common.targets: error : 'OutputPath' property is not set for this project. Usually this is caused by invalid Configuration/Platform combination. Original values: Configuration: Release Platform: Linux.
                                    Task "Error" execution -- FAILED
                                    Done building target "_ValidateEssentialProperties" in project "/media/windows/share/Eto/Source/Eto.Direct2D/Eto.Direct2D.csproj".-- FAILED
                                Done building project "/media/windows/share/Eto/Source/Eto.Direct2D/Eto.Direct2D.csproj".-- FAILED
                            Task "MSBuild" execution -- FAILED
                            Done building target "GetCopyToOutputDirectoryItems" in project "/media/windows/share/Eto/Source/Eto.Test/Eto.Test.Direct2D/Eto.Test.Direct2D.csproj".-- FAILED
                        Done building project "/media/windows/share/Eto/Source/Eto.Test/Eto.Test.Direct2D/Eto.Test.Direct2D.csproj".-- FAILED
                    Task "MSBuild" execution -- FAILED
                    Done building target "GetCopyToOutputDirectoryItems" in project "/media/windows/share/Eto/Source/Eto.Test/Eto.Test.WinForms/Eto.Test.WinForms.csproj".-- FAILED
                Done building project "/media/windows/share/Eto/Source/Eto.Test/Eto.Test.WinForms/Eto.Test.WinForms.csproj".-- FAILED
            Task "MSBuild" execution -- FAILED
            Done building target "Build" in project "/media/windows/share/Eto/Source/Eto - net40.sln".-- FAILED
        Done building project "/media/windows/share/Eto/Source/Eto - net40.sln".-- FAILED
        Build FAILED.
        Errors:
        /media/windows/share/Eto/Source/Eto - net40.sln (Build) ->
        (Build target) ->
        /media/windows/share/Eto/Source/Eto.Test/Eto.Test.WinForms/Eto.Test.WinForms.csproj (default targets) ->
        /usr/lib/mono/4.5/Microsoft.Common.targets (GetCopyToOutputDirectoryItems target) ->
        /media/windows/share/Eto/Source/Eto.Test/Eto.Test.Direct2D/Eto.Test.Direct2D.csproj (GetCopyToOutputDirectoryItems) ->
        /usr/lib/mono/4.5/Microsoft.Common.targets (GetCopyToOutputDirectoryItems target) ->
        /media/windows/share/Eto/Source/Eto.Direct2D/Eto.Direct2D.csproj (GetCopyToOutputDirectoryItems) ->
        /usr/lib/mono/4.5/Microsoft.Common.targets (_ValidateEssentialProperties target) ->
            /usr/lib/mono/4.5/Microsoft.Common.targets: error : 'OutputPath' property is not set for this project. Usually this is caused by invalid Configuration/Platform combination. Original values: Configuration: Release Platform: Linux.