Provide %{buildDir} macro expansion again.

This was a regression introduced during the macro expander rework.

Task-number: QTCREATORBUG-13260
Change-Id: I9fd28c6a522faa11992931f937dd0b0eb779f419
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/plugins/projectexplorer/runconfiguration.cpp

@@ -253,6 +253,8 @@ void RunConfiguration::addExtraAspect(IRunConfigurationAspect *aspect)
 void RunConfiguration::ctor()
 {
     connect(this, SIGNAL(enabledChanged()), this, SIGNAL(requestRunActionsUpdate()));
+
+    macroExpander()->registerSubProvider([this] { return target()->macroExpander(); });
 }
 
 /*!