mythcommflag is a backend process. It should be included when the "backendonly" use flag is used. mythtranscode is in the same category. Reproducible: Always Steps to Reproduce: 1. Add backendonly to make.conf or package.use 2. emerge mythtv 3. Notice that several backend processes aren't installed Expected Results: mythcommflag and mythtranscode would be installed media-tv/mythtv-0.20_p12325
backendonly USE flag is not guaranteed to compile every app. It only compiles the essentials for the backend. It also says that if you choose to use it and something is missing, there's no support for that. Upstream only supports the full build.
*** Bug 198530 has been marked as a duplicate of this bug. ***