[Qt-interest] How can I use the system envoriment variable in qt project file(.pro) ?

[Kermit Mei]

Hello Community!

  How can I use the Linux system variable such as $PATH $QTDIR in .pro
file ?
  For example, I want to use:
  LIBS += -L$QTDIR/lib -lgui

I want the compiler use argument "-L/opt/qt/lib -lgui" where
$QTDIR=/opt/qt

How to do that?

Thanks

Kermit