vadimi

<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
		<ScriptsDir>Layouts\MyCoolProject\Scripts</ScriptsDir>
		<ManifestPath>pkg\Release\MyCoolProject</ManifestPath>
	</PropertyGroup>
	<ItemGroup>
		<ExcludedFiles Include="
			$(ScriptsDir)\jquery-1.9.1.js;
			$(ScriptsDir)\backbone.js;
			$(ScriptsDir)\backbone-sharepoint.extensions.js;

vadimi

<Target Name="BeforeLayout" Condition="'$(Configuration)'=='Release'">
    <FindInEnumeration Files="@(ExcludedFiles)" SourceFiles="@(EnumeratedFiles)">
      <Output ItemName="Result" TaskParameter="Result" />
    </FindInEnumeration>
    <ItemGroup>
      <EnumeratedFiles Remove="@(Result)"/>
    </ItemGroup>
</Target>

vadimi

<UsingTask TaskName="FindInEnumeration" TaskFactory="CodeTaskFactory"
  		   AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
	<ParameterGroup>
		<SourceFiles ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
		<Files ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
		<Result ParameterType="Microsoft.Build.Framework.ITaskItem[]" Output="true" />
	</ParameterGroup>
	<Task>
		<Reference Include="System" />
		<Reference Include="System.Core" />