qtbase5-private-dev qt include in 5.11.1

Hello
I am using the qt QXLSX library that needs the qtbase5-private-dev (module/library or what ever that is)
And my installation of Qt from the Qt site (version that I chose to work with is 5.11.1) didnt have that module/library
I ended with installing it from ubuntu itself with sudo apt-get install qtbase5-private-dev and using the ubuntu version of Qt which is 5.2.1
Is there any way to add this library to my stand alone Qt install?
Thanks in advanced

You have it but you probably don't know it.