QX11EmbedContainer not working

[brainTech]

Hi,
I want to user QX11EmbedContainer but it is not working. Qtcreator is giving compilation error on making instance of it: QX11EmbedContainer *container = new QX11EmbedContainer();

Error: Undefined symbols for architecture x64 QX11EmbedContainer :: QX11EmbedContainer(QWidget*)

Can anyone please guide me how to get it working?
MacOS: 10.7.x
Qt: 4.8.1

Thank you in advance.