This is an auto-filled bug because dev-libs/libratbag fails to compile. The issue was originally discovered on amd64, but it may be reproducible on other arches as well. If you think that a different summary clarifies the issue better, feel free to change it. Attached build log and emerge --info. NOTE: If you need further logs, feel free to ask..
Created attachment 638996 [details] build.log build log and emerge --info
Note: 0.13 (bug #682372) also wants dev-util/valgrind.
If this is still an issue with dev-libs/libratbag-0.15 please file a new bug.