How to get KDE4 for building a project in Ubuntu 12.04?
Build depends
The Krusader 'Build-Depends': http://archive.ubuntu.com/ubuntu/pool/universe/k/krusader/krusader_2.4.0~beta3-2.dsc
=> cmake, debhelper (>= 9), kdelibs5-dev (>= 4:4.4.4), libkonq5-dev, pkg-kde-tools (>= 0.9.0), zlib1g-dev
The KDE development packages are: kdelibs5-dev and libkonq5-dev
According to the 'Compilation requirements' (thanks to comment by user26687), kdelibs5-dev is required. In the Synaptic it was marked as not installed (no green mark) and supported (Red Ubuntu symbol). I have installed it by
me_user@myCPU:~$ sudo apt-get install kdelibs5-dev. After it the command
find_package(KDE4 REQUIRED)is accepted by Qt.