dev-util/kdbg-2.1.1 was released on 2008-12-20.
Kdbg 2.1.0 no longer compiles properly with kdelibs-3.5.10 for me. As older kdelibs don't coexist nicely with kde the only way to get a working kdbg on kde4 (for me) is to move to 2.1.1. I have done a bump on the ebuild and it is working correctly for me on amd64. As it is a very simple ebuild I don't think anything other then a bump is needed.
Created attachment 184045 [details] Bumped ebuild
+*kdbg-2.1.1 (25 Apr 2009) + + 25 Apr 2009; Patrick Lauer <patrick@gentoo.org> +kdbg-2.1.1.ebuild: + Bump to 2.1.1, fixes #252440