Can't add Multimedia module in .pro

[A Former User]

I'm trying to add multimediamodule in .pro like this: QT += core qml quick widgets multimedia svg xml, but it creates many errors:

If I remove multimedia and add it again it will compile and run without errors. But as soon as I add something new to code, even just a variable like int a; it will ruin and show the same errors as above. I tried multimediawidgets too.

I'm using Qt 5.5.