Well, it certainly depends on the features that you want enabled on your platform. The syslog-ng configure script allows tailor-made configurations at a pretty granular level. But I guess it would make sense to compile syslog-ng for your use-case.
syslog-ng has not - yet - been optimized too much for the embedded use-case, but it is generally slim package implemented in C, so it should be possible. The dependency I'd be afraid the most is glib, which has grown pretty fat in recent times. There an earlier release could be enough (2.14 should be ok).