the development of ffmpeg has deprecated and removed various apis that zoneminder uses if you are running into compiler errors around ffmpeg and are using their code repo or a latest snapshot this should fix your issues.
The ffmpeg fixes are in the branch:
https://github.com/mitchcapper/ZoneMind ... mpeg_fixes
Note right now you can just get a patch from the commit that has all the current changes at:
https://github.com/mitchcapper/ZoneMind ... 435b.patch