Your mips CC was removed without explanation or handling of the required task from bug without any kind of explanation (probably arfrever mistook the mips CC as a wrong one on a stabilization bug while the comment clearly said it's for handling the stale keyword situation of it), so here's a separate keywordreq bug for you. Please either keyword a newer version of dev-cpp/libxmlpp than the very very old libxmlpp-2.12.0 or drop the keyword entirely if you seem that appropriate and nothing uses it. Thanks.
Sorry, somehow missed the bug number of the earlier libxmlpp bug. The old bug was 222749 that had requested keywording of newer version or dropping keyword completely. Also updating summary to include the term "newer version"
Dropped ~mips keyword with my mips team hat on, and removed 2.12 libxmlpp ebuild therefore completely with my gnome team hat on. Mips will re-keyword a newer version if they ever want an application or library that actually depends on it. Currently none of the in-tree packages that have libxmlpp in their deptree have any mips keywords.