Sylpheed 1.0.0 has been released on December 24th. There are almost no changes to the ebuild needed, but I'll attach the ebuild with which it compiled and runs fine for me. Reproducible: Always Steps to Reproduce: 1. 2. 3.
Created attachment 47735 [details] ebuild for sylpheed 1.0.0
Fixed in CVS. Thank you for reporting!