btsync also requires Linux 2.6.16 or later, and the DNS-323 is 2.6.12 (as of latest firmware). So I think it's a no-go. There is an alternate firmware for the DNS-323, Alt-F (currently in release candidate stage). https://code.google.com/p/alt-f/. I have not tried this firmware, but I do note that it is running Linux 2.6.35. There is still the glibc issue, though. https://groups.google.com/forum/?fromgroups=#!topic/alt-f/56JpDW3UxCg. Perhaps the workaround that rdebath linked to, using Alt-F firmware, will lead to a solution.
