title: Build All projects in a directory
body: <p>Im try to build my plugins that sit in a seperate directory on the root.</p>
  
  <pre><code>  &lt;ItemGroup&gt;
      &lt;PluginProjectFiles Include="$(MSBuildStartupDirectory)..\..\Plugins\**\*.csproj"/&gt;
    &lt;/ItemGroup&gt;
    &lt;Target Name="BuildPlugins"&gt;
      &lt;MSBuild Projects="@(PluginProjectFiles)" Targets="Clean;Build" Properties="Configuration=Release" /&gt;
      &lt;Message Text="Dir: $(MSBuildStartupDirectory)" /&gt;
    &lt;/Target&gt;
  </code></pre>
  
  <p>Although im having problems. My build runs the 'BuildPlugin' Target but it doesn't build my project files. I really don't want to have to build each project separately if I can avoid it.</p>
  
  <p>Any ideas would be great. Thanks,</p>