With vdr-2.1.6, proper systemd support has been added, which is optionally activated via the SDNOTIFY build symbol given to the make invocation. Also, then we have a build dependency to sys-apps/systemd. This can be nicely controlled by the systemd USE flag. Reproducible: Always
Created attachment 386018 [details, diff] ebuild patch to add systemd support
added to media-video/vdr-2.1.6-r2 thx for reporting this