Rewrite nuspecs earlier

Author: MackinnonBuck

eng/AfterSolutionBuild.targets

@@ -38,6 +38,20 @@
       SkipGetTargetFrameworkProperties="true" />
   </ItemGroup>
 
+  <!-- This is temporary until we can use FrameworkReference to build our own packages. -->
+  <Target Name="RemoveSharedFrameworkOnlyRefsFromNuspec" BeforeTargets="Build;BuildDelayedProjects"
+      Condition=" '$(MSBuildRuntimeType)' == 'core' ">
+    <ItemGroup>
+      <_BuildOutput Include="$(ArtifactsShippingPackagesDir)*.nupkg"
+                    Exclude="$(ArtifactsShippingPackagesDir)*.symbols.nupkg" />
+    </ItemGroup>
+
+    <RepoTasks.RemoveSharedFrameworkDependencies Condition="'@(_BuildOutput->Count())' != '0'"
+      Files="@(_BuildOutput)"
+      FrameworkOnlyPackages="@(AspNetCoreAppReference)"
+      SharedFrameworkTargetFramework="$(DefaultNetCoreTargetFramework)" />
+  </Target>
+
   <!-- Cannot build in source-build because that does not create an App.Ref layout. -->
   <Target Name="BuildDelayedProjects"
       BeforeTargets="Build"