Multi-targeted .netstandard csproj in VS for Mac

ProjectName.csproj

<?xml version="1.0" encoding="utf-8"?>
<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <TargetFrameworks>netstandard2.0;Xamarin.iOS10;MonoAndroid81;</TargetFrameworks>
        <SynchReleaseVersion>false</SynchReleaseVersion>
        <DefineConstants>$(DefineConstants);</DefineConstants>
        <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
        <Configurations>Debug;Release;</Configurations>
    </PropertyGroup>
    <PropertyGroup Condition=" '$(Configuration)'=='Debug' ">
        <DebugType>full</DebugType>
        <DebugSymbols>true</DebugSymbols>
    </PropertyGroup>
    <ItemGroup>
        <PackageReference Include="MSBuild.Sdk.Extras" Version="1.6.60" PrivateAssets="All" />
        <PackageReference Include="Newtonsoft.Json" Version="12.0.1" />
        <Compile Include="**\*.shared.cs" />
    </ItemGroup>
    <ItemGroup Condition=" $(TargetFramework.StartsWith('netstandard')) ">
        <Compile Include="**\*.netstandard.cs" />
    </ItemGroup>
    <ItemGroup Condition=" $(TargetFramework.StartsWith('MonoAndroid')) ">
        <Compile Include="**\*.android.cs" />
    </ItemGroup>
    <ItemGroup Condition=" $(TargetFramework.StartsWith('Xamarin.iOS')) ">
        <Reference Include="OpenTK-1.0" />
        <Compile Include="**\*.ios.cs" />
    </ItemGroup>
    <ItemGroup>
        <None Include="**\*.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
    </ItemGroup>
    <Import Project="$(MSBuildSDKExtrasTargets)" Condition="Exists('$(MSBuildSDKExtrasTargets)')" />
</Project>