Write a custom .pro file for your project and sav it in the project dir. See
http://doc.trolltech.com/4.0/qmake-manual.htmlIn tools menu add a tool:
Name: QMake
Executable: QTDIR/bin/qmake (replace QTDIR)
Parameters: -o Makefile.qmake (or whatever name you want)
Working Dir: ${PROJECTDIR}
In Settings->Compiler Settings->Other select "build using makefiles" (not sure if needed anymore)
In Project->Properties tick "This is a custom makefile" and write Makefile.qmake in the Makefile:
Now select Tools->QMake and then Build->Build and voila
Be warned that you overide the whole build system of codeblocks and that you have to write the .pro file yourself (qmake can also generate one for you but I like writing my own).
And as of my Qt plugin status it can build
I am almost finished with the .pro generator and from there on it's all about making it user friendly