QtCreator subdirs - Dependencies of project

I have my project organized with subdirs template:
Project
---Dir1
---Dir2
---LibDir

Every time when I make changes in LibDir and press the Build button I got error from Dir1 or Dir2 like:
error: undefined reference to `_imp___ZN6LibDir8FuncE7QStringS0_bbb'

So how can I set that Dir1 was dependent on LibDir?

You can use CONFIG += ordered in your main project and have the lib projects listed first.