Qt not detecting system theme by default

[ChajusSaib]

So I went to build Qt statically.

./configure -static -release -gtkstyle -prefix /home/chajussaib/Qt/OtherBuilds/QtStaticBuildGtk -nomake examples -nomake tools

Everything went well and I built my application however I must force it to use GTK instead of it using it be default like how the pre-built one does.

./TextEditor -style=gtk

On Linux Mint 17.2 Cinnamon
How come?