Without =app-text/docbook-xml-dtd-4.1* installed, we get the same symptoms as in bug #198622 (and other). This problem affects both gnome-games-2.28* and gnome-games-2.30* ebuilds. Reproducible: Always
A build.log and an emerge --info are still required.
Created attachment 273209 [details] emerge --info
Created attachment 273211 [details] build.log failure
I've tried to reproduce this problem on my system again (removing =app-text/docbook-xml-dtd-4.1* and re-emerging gnome-games) but now it vanished. It seems docbook-xml-dtd-4.1 installation changed scrollkeeper/docbook/anything else setup and "fixed" the problem for me). This problem is similar to other issues with the same error log like: bug #198622. As you can see, in that bug we also get 'can't reproduce after install/uninstall' symptom; see comment #7).
Ok this is actually due to a corruption of the catalog file or whatever just as noted in bug #128952. Please provide information there next time you see this problem. *** This bug has been marked as a duplicate of bug 128952 ***