diff --git a/Directory.Build.props b/Directory.Build.props
index 91a53350..ac39cb16 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -1,9 +1,9 @@
 <Project>
- <PropertyGroup>
-   <NoWarn>CS1591;CS0219;8002;NU5125</NoWarn>
-   <SolutionDir Condition="'$(SolutionDir)'==''">$(MSBuildThisFileDirectory)</SolutionDir>
- </PropertyGroup>
- <PropertyGroup Condition="$(TargetFramework.StartsWith('net4'))">
+  <PropertyGroup>
+    <NoWarn>CS1591;CS0219;8002;NU5125</NoWarn>
+    <SolutionDir Condition="'$(SolutionDir)'==''">$(MSBuildThisFileDirectory)</SolutionDir>
+  </PropertyGroup>
+  <PropertyGroup Condition="$(TargetFramework.StartsWith('net4'))">
     <DefineConstants>$(DefineConstants);NETFRAMEWORK</DefineConstants>
   </PropertyGroup>
   <!-- Enable building .NET Framework projects on any machine with at least MSBuild or the .NET Core SDK installed.-->
@@ -12,5 +12,10 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
+    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
+  </ItemGroup>
+  <ItemGroup>
+    <!-- Compiler to support nullable in VS2017 -->
+    <PackageReference Include="Microsoft.Net.Compilers.Toolset" Version="3.4.0" PrivateAssets="All" />
   </ItemGroup>
 </Project>
diff --git a/src/CommandLine/CommandLine.csproj b/src/CommandLine/CommandLine.csproj
index 7624b2e7..182013f7 100644
--- a/src/CommandLine/CommandLine.csproj
+++ b/src/CommandLine/CommandLine.csproj
@@ -1,51 +1,53 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <PropertyGroup>
-    <AssemblyName>CommandLine</AssemblyName>
-    <OutputType>Library</OutputType>
-    <TargetFrameworks>netstandard2.0;net40;net45;net461</TargetFrameworks>
-    <DefineConstants>$(DefineConstants);CSX_EITHER_INTERNAL;CSX_REM_EITHER_BEYOND_2;CSX_ENUM_INTERNAL;ERRH_INTERNAL;ERRH_DISABLE_INLINE_METHODS;CSX_MAYBE_INTERNAL;CSX_REM_EITHER_FUNC</DefineConstants>
-    <DefineConstants Condition="'$(BuildTarget)' != 'fsharp'">$(DefineConstants);SKIP_FSHARP</DefineConstants>
-    <GenerateDocumentationFile>true</GenerateDocumentationFile>
-    <AssemblyOriginatorKeyFile>..\..\CommandLine.snk</AssemblyOriginatorKeyFile>
-	
-    <SignAssembly>true</SignAssembly>
-    <PackageId Condition="'$(BuildTarget)' != 'fsharp'">CommandLineParser</PackageId>
-    <PackageId Condition="'$(BuildTarget)' == 'fsharp'">CommandLineParser.FSharp</PackageId>
-    <Authors>gsscoder;nemec;ericnewton76</Authors>
-    <Title>Command Line Parser Library</Title>
-    <Version Condition="'$(VersionSuffix)' != ''">$(VersionSuffix)</Version>
-    <Version Condition="'$(VersionSuffix)' == ''">0.0.0</Version>
-    <Description Condition="'$(BuildTarget)' != 'fsharp'">Terse syntax C# command line parser for .NET.  For FSharp support see CommandLineParser.FSharp.  The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.</Description>
-    <Description Condition="'$(BuildTarget)' == 'fsharp'">Terse syntax C# command line parser for .NET with F# support. The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.</Description>
-    <Copyright>Copyright (c) 2005 - 2018 Giacomo Stelluti Scala &amp; Contributors</Copyright>
-	<PackageLicenseFile>License.md</PackageLicenseFile>
-	<PackageIcon>CommandLine20.png</PackageIcon>
-    <PackageProjectUrl>https://github.com/commandlineparser/commandline</PackageProjectUrl>
-    <PackageTags>command line;commandline;argument;option;parser;parsing;library;syntax;shell</PackageTags>
-    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <LangVersion>7.3</LangVersion>
-  </PropertyGroup>
+	<PropertyGroup>
+		<AssemblyName>CommandLine</AssemblyName>
+		<OutputType>Library</OutputType>
+		<TargetFrameworks>netstandard2.0;net40;net45;net461</TargetFrameworks>
+		<DefineConstants>$(DefineConstants);CSX_EITHER_INTERNAL;CSX_REM_EITHER_BEYOND_2;CSX_ENUM_INTERNAL;ERRH_INTERNAL;ERRH_DISABLE_INLINE_METHODS;CSX_MAYBE_INTERNAL;CSX_REM_EITHER_FUNC</DefineConstants>
+		<DefineConstants Condition="'$(BuildTarget)' != 'fsharp'">$(DefineConstants);SKIP_FSHARP</DefineConstants>
+		<GenerateDocumentationFile>true</GenerateDocumentationFile>
+		<AssemblyOriginatorKeyFile>..\..\CommandLine.snk</AssemblyOriginatorKeyFile>
+		<SignAssembly>true</SignAssembly>
+		<PackageId Condition="'$(BuildTarget)' != 'fsharp'">CommandLineParser</PackageId>
+		<PackageId Condition="'$(BuildTarget)' == 'fsharp'">CommandLineParser.FSharp</PackageId>
+		<Authors>gsscoder;nemec;ericnewton76</Authors>
+		<Title>Command Line Parser Library</Title>
+		<Version Condition="'$(VersionSuffix)' != ''">$(VersionSuffix)</Version>
+		<Version Condition="'$(VersionSuffix)' == ''">0.0.0</Version>
+		<Description Condition="'$(BuildTarget)' != 'fsharp'">Terse syntax C# command line parser for .NET.  For FSharp support see CommandLineParser.FSharp.  The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.</Description>
+		<Description Condition="'$(BuildTarget)' == 'fsharp'">Terse syntax C# command line parser for .NET with F# support. The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.</Description>
+		<Copyright>Copyright (c) 2005 - 2018 Giacomo Stelluti Scala &amp; Contributors</Copyright>
+		<PackageLicenseFile>License.md</PackageLicenseFile>
+		<PackageIcon>CommandLine20.png</PackageIcon>
+		<PackageProjectUrl>https://github.com/commandlineparser/commandline</PackageProjectUrl>
+		<PackageTags>command line;commandline;argument;option;parser;parsing;library;syntax;shell</PackageTags>
+		<GeneratePackageOnBuild>true</GeneratePackageOnBuild>
+		<LangVersion>8.0</LangVersion>
+		<IncludeSymbols>true</IncludeSymbols>
+		<DebugType>portable</DebugType>
+		<!--<SymbolPackageFormat>snupkg</SymbolPackageFormat>-->
+	</PropertyGroup>
 
-  <ItemGroup Condition="'$(BuildTarget)' != 'fsharp'">
-    <Compile Remove="Infrastructure\FSharpOptionHelper.cs" />
-  </ItemGroup>
+	<ItemGroup Condition="'$(BuildTarget)' != 'fsharp'">
+		<Compile Remove="Infrastructure\FSharpOptionHelper.cs" />
+	</ItemGroup>
 
-  <ItemGroup>
-    <Content Include="..\..\README.md" Link="README.md">
-      <Pack>true</Pack>
-      <PackagePath>README.md</PackagePath>
-    </Content>
-  </ItemGroup>
+	<ItemGroup>
+		<Content Include="..\..\README.md" Link="README.md">
+			<Pack>true</Pack>
+			<PackagePath>README.md</PackagePath>
+		</Content>
+	</ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' != 'net40' and '$(BuildTarget)' == 'fsharp'">
-    <PackageReference Include="FSharp.Core" Version="4.5.1" Condition="'$(BuildTarget)' == 'fsharp'" />
-  </ItemGroup>
-  <ItemGroup Condition="'$(TargetFramework)' == 'net40' and '$(BuildTarget)' == 'fsharp'">
-    <PackageReference Include="FSharp.Core" Version="4.0.0.1" Condition="'$(BuildTarget)' == 'fsharp'" />
-  </ItemGroup>
-  <ItemGroup>
-    <None Include="$(SolutionDir)LICENSE.md" Pack="true" PackagePath=""/>
-    <None Include="$(SolutionDir)art\CommandLine20.png" Pack="true" PackagePath=""/>
-  </ItemGroup>
+	<ItemGroup Condition="'$(TargetFramework)' != 'net40' and '$(BuildTarget)' == 'fsharp'">
+		<PackageReference Include="FSharp.Core" Version="4.5.1" Condition="'$(BuildTarget)' == 'fsharp'" />
+	</ItemGroup>
+	<ItemGroup Condition="'$(TargetFramework)' == 'net40' and '$(BuildTarget)' == 'fsharp'">
+		<PackageReference Include="FSharp.Core" Version="4.0.0.1" Condition="'$(BuildTarget)' == 'fsharp'" />
+	</ItemGroup>
+	<ItemGroup>
+		<None Include="$(SolutionDir)LICENSE.md" Pack="true" PackagePath=""/>
+		<None Include="$(SolutionDir)art\CommandLine20.png" Pack="true" PackagePath=""/>
+	</ItemGroup>
 </Project>