I was able to compile the following code:
Qt Code: 
  1. #include <QTcpSocket>
  2. #include <QApplication>
  3.  
  4. int main(int argc, char *argv[])
  5. {
  6. 	QApplication app(argc, argv);
  7. 	QTcpSocket * socket = new QTcpSocket();
  8. 	socket->connectToHost("imap.free.fr", 143);
  9. 	return app.exec();
  10. }
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With this pro file:
Qt Code: 
  1. ######################################################################
  2. # Automatically generated by qmake (2.01a) Fri Feb 23 09:05:34 2007
  3. ######################################################################
  4.  
  5. QT += network
  6. TEMPLATE = app
  7. TARGET = 
  8. DEPENDPATH += .
  9. INCLUDEPATH += .
  10.  
  11. # Input
  12. SOURCES += main.cpp
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mAx