I'm using Ubuntu 10.4 to compile my project. Since the installed Qt is 4.6, I reinstalled Qt 4.8. But when I try to compile my program, it gives me the error "cannot find 'phonon' no such file or directory".

The steps I did are:
1. Dowload "Qt libraries 4.8.4 for Linux/X11 (225 MB)" fromhttp://qt-project.org/downloads
2. Decompress the package and run "./configure" in the directory.
3. Run "make" and then run "sudo make install", Qt 4.8 is installed into "/usr/local/Trolltech". I checked the new installed "lib" folder but there's no "phonon" inside.
4. Use "sudo apt-get install libphonon-dev phonon-backend-gstreamer" to install the phonon libraries.
5. Going to my project, make sure the .pro file contains "QT += phonon" and compile the program.

The problem is when I use the 4.6 qamke (in /usr/share/) to compile, there's no phonon missing error.
But when I use 4.8, the error raises.

Thanks in advance.