[MSBuild] Allow excluding types from an assembly when generating intersection

<ItemGroup>
  <IntersectionExcludeAssembly Include="path/to/assembly.dll" />
</ItemGroup>

Maps to the -e parameter used by ApiIntersect.

Author: mrward

src/Build/NuGet.Build.Packaging.Tasks/ApiIntersect.cs

@@ -21,6 +21,8 @@ public class ApiIntersect : ToolTask
 
 		public ITaskItem[] RemoveAbstractTypeMembers { get; set; }
 
+		public ITaskItem[] ExcludeAssembly { get; set; }
+
 		public string KeepInternalConstructors { get; set; }
 
 		public string KeepMarshalling { get; set; }
@@ -88,6 +90,12 @@ protected override string GenerateCommandLineCommands()
 				builder.AppendTextUnquoted("\"");
 			}
 
+			foreach (var assembly in ExcludeAssembly.NullAsEmpty())
+			{
+				builder.AppendSwitch("-e");
+				builder.AppendFileNameIfNotNull(assembly.ItemSpec);
+			}
+
 			AppendSwitchIfTrue(builder, "-k", KeepInternalConstructors);
 
 			AppendSwitchIfTrue(builder, "-m", KeepMarshalling);

src/Build/NuGet.Build.Packaging.Tasks/NuGet.Build.Packaging.targets

@@ -524,6 +524,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 			ReferencePath="$(IntersectionAssemblyReferencePath)"
 			ExcludeType="$(IntersectionExcludeType)"
 			RemoveAbstractTypeMembers="$(IntersectionRemoveAbstractTypeMembers)"
+			ExcludeAssembly="@(IntersectionExcludeAssembly)"
 			KeepInternalConstructors="$(IntersectionKeepInternalConstructors)"
 			KeepMarshalling="$(IntersectionKeepMarshalling)"
 			ToolPath="$(ApiIntersectToolPath)"