Apparently some people tap into this pitfall, so I’ll kinda “announce” this here. KDevelop4 from trunk requires kdebase/workspace since this week. The reason is a much improved process-selection-widget for our gdb-plugin. This allows far better attach-to-process experience than the old widget. The new widget comes from a library thats so far used by ksysguard and is installed as part of the KDE workspace. For KDE 4.4 the library will move to kdelibs and then this requirement will be lifted again, but until then the best option we have is depending on kdebase/workspace.
Also I’d like to note that right now OpenSuSE and Gentoo packages for kdebase/workspace have a bug, which prevents automatic finding of the relevant cmake modules when building KDevelop. Amilcar posted a workaround to the kdevelop mailinglists, but I’m pretty sure the distro’s will catch up soon with fixed packages.