Rename file, add license header, fix spacing, use different compile item

Author: ellahathaway

src/AssemblyInfo.cs

@@ -0,0 +1,4 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+[assembly: System.Reflection.AssemblyMetadata("source", "source-build-reference-packages")]

src/SourceBuildAssemblyMetdata.cs

@@ -4,7 +4,7 @@
 
   <ItemGroup>
     <!-- Attributes for all Reference Packages -->
-    <Compile Include="$(RepoRoot)src\AssemblyInfo.cs" />
+    <Compile Include="$(RepoRoot)src\SourceBuildAssemblyMetdata.cs" />
   </ItemGroup>
 
   <PropertyGroup>

src/referencePackages/Directory.Build.props

@@ -122,15 +122,16 @@
           AfterTargets="CopyFilesToOutputDirectory">
 
     <ItemGroup>
-      <Compile Remove="$(RepoRoot)src\AssemblyInfo.cs" />
+      <CompileForRelativePath Include="@(Compile)" />
+      <CompileForRelativePath Remove="$(RepoRoot)src\SourceBuildAssemblyMetdata.cs" />
     </ItemGroup>
 
     <Error
-      Condition="@(Compile->Count()) != 1"
+      Condition="@(CompileForRelativePath->Count()) != 1"
       Text="Number of Compile items != 1. We need just one, to determine the path of the resulting DLL in the package including ref/lib and TFM." />
 
     <ItemGroup>
-      <FullCompileDir Include="$([System.IO.Directory]::GetParent('%(Compile.Identity)'))" />
+      <FullCompileDir Include="$([System.IO.Directory]::GetParent('%(CompileForRelativePath.Identity)'))" />
       <RelativeCompileDir Include="$([MSBuild]::MakeRelative('$(MSBuildProjectDirectory)\', '%(FullCompileDir.Identity)'))" />
     </ItemGroup>
 

src/referencePackages/Directory.Build.targets

@@ -1,10 +1,10 @@
 <Project>
   <Import Project="..\..\Directory.Build.props" />
 
-    <ItemGroup>
-      <!-- Attributes for all Target Packages -->
-      <Compile Include="$(RepoRoot)src\AssemblyInfo.cs" />
-    </ItemGroup>
+  <ItemGroup>
+    <!-- Attributes for all Target Packages -->
+    <Compile Include="$(RepoRoot)src\SourceBuildAssemblyMetdata.cs" />
+  </ItemGroup>
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>