title: How I pack a multi-target package with MSBuild 15?
body: <p>I am using the new MSBuild 15 distributed with VS2017 RC to compile and pack a multi targeting project.</p>
  
  <p>Restoring: <code>msbuild /t:restore mysolution.sln</code> works correctly.</p>
  
  <p>Building: <code>msbuild /p:Configuration=Release mylibrary.csproj</code> works correctly and generates:</p>
  
  <pre><code>+ bin/Release
    + netstandard1.4
      - mylibrary.dll
    + net452
      - mylibrary.dll
  </code></pre>
  
  <p>But when I am packing: <code>msbuild /t:pack /p:Configuration=Release /p:IncludeSymbols=true mylibrary.csproj</code> the structure does not match well with the previous build, looking like:</p>
  
  <pre><code>+ bin/Release
    + netstandard1.4
      - mylibrary.pdb
    + net452
      - mylibrary.pdb
    - mylibrary.dll
  </code></pre>
  
  <p>Warnings from the <code>/t:pack</code> command show me this was gonna happen, but not sure how to solve it:</p>
  
  <pre><code>C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Sdks\NuGet.Build.Tasks.Pack\buildCrossTargeting\NuGet.Build.Tasks.Pack.targets(73,5): warning : Issue found with package 'MyLibrary'. [D:\XXX\YYY\src\MyLibrary\MyLibrary.csproj]
  C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Sdks\NuGet.Build.Tasks.Pack\buildCrossTargeting\NuGet.Build.Tasks.Pack.targets(73,5): warning : Issue: Assembly not inside a framework folder. D:\XXX\YYY\src\MyLibrary\MyLibrary.csproj]
  C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Sdks\NuGet.Build.Tasks.Pack\buildCrossTargeting\NuGet.Build.Tasks.Pack.targets(73,5): warning : Description: The assembly 'lib\MyLibrary.dll' is placed directly under 'lib' folder. It is recommended that assemblies be placed inside a framework-specific folder.
  C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\Sdks\NuGet.Build.Tasks.Pack\buildCrossTargeting\NuGet.Build.Tasks.Pack.targets(73,5): warning : Solution: Move it into a framework-specific folder. If this assembly is targeted for multiple frameworks, ignore this warning.
  </code></pre>
  
  <p>Notes:</p>
  
  <p>I am not using a <code>*.nuspec</code> file. Just the new way <code>*.csproj</code> files work (<a href="https://docs.nuget.org/ndocs/schema/msbuild-targets#pack-target" rel="noreferrer">https://docs.nuget.org/ndocs/schema/msbuild-targets#pack-target</a>)</p>
  
  <p>This is how some of the relevant content of the file look like:</p>
  
  <pre><code>&lt;Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"&gt;
          &lt;PropertyGroup&gt;
              &lt;OutputType&gt;library&lt;/OutputType&gt;
              &lt;TargetFrameworks&gt;netstandard1.4;net452&lt;/TargetFrameworks&gt;
              &lt;AssemblyName&gt;MyLibrary&lt;/AssemblyName&gt;
              &lt;Authors&gt;XXX&lt;/Authors&gt;
              &lt;Description&gt;YYY&lt;/Description&gt;
              &lt;PackageId&gt;MyLibrary&lt;/PackageId&gt;
              &lt;PackageVersion&gt;1.2.3&lt;/PackageVersion&gt;
          &lt;/PropertyGroup&gt;
  &lt;/Project&gt;
  </code></pre>