Umbraco-CMS: Can not build with build.ps1

I can’t build Umbraco from source:

Bug summary

Exception calling "RunMethod" with "1" argument(s): "Exception calling "Build" with "0" argument(s): "Exception
calling "CompileUmbraco" with "0" argument(s): "Failed to compile Umbraco.Web.UI."""
At C:\Users\Jonathan\Desktop\Umbraco\Umbraco-CMS\build\build.ps1:561 char:5
+     $ubuild.RunMethod($command);
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ScriptMethodRuntimeException

Error!

MethodInvocationException: Exception calling "RunMethod" with "1" argument(s): "Exception calling "Build" with "0" argument(s): "Exception calling "CompileUmbraco" with "0" argument(s): "Failed to compile Umbraco.Web.UI."""
At C:\Users\Jonathan\Desktop\Umbraco\Umbraco-CMS\build\build.ps1:561:5
+ $ubuild.RunMethod($command);

MethodInvocationException: Exception calling "Build" with "0" argument(s): "Exception calling "CompileUmbraco" with "0" argument(s): "Failed to compile Umbraco.Web.UI.""
At C:\Users\Jonathan\Desktop\Umbraco\Umbraco-CMS\build\temp\Umbraco.Build.0.2.16\ps\Boot.ps1:35:5
+ $method.Invoke($arguments)

MethodInvocationException: Exception calling "CompileUmbraco" with "0" argument(s): "Failed to compile Umbraco.Web.UI."
At C:\Users\Jonathan\Desktop\Umbraco\Umbraco-CMS\build\build.ps1:510:5
+ $this.CompileUmbraco()

RuntimeException: Failed to compile Umbraco.Web.UI.
At C:\Users\Jonathan\Desktop\Umbraco\Umbraco-CMS\build\build.ps1:197:20
+ if (-not $?) { throw "Failed to compile Umbraco.Web.UI." }

Abort

Steps to reproduce

By following the guide (BUILD.md):

1. git clone Umbraco-CMS (being on the v8/contrib branch)
2. run build.ps1

Ends up raising the exception above.