This was added to OpenLDAP 2.4.18 release, however the ifdef about DEVEL was never removed. The intent was to make it usable with 2.4.18 and later. I'm guessing the ifdef should be removed now in HEAD, at which point I'll sync it to RE24?
This was added with the intent of providing support for static tcp buffers sizing in Linux. I guess it needs some work to ensure portability, but I'd rather leave this to someone that can check it with different archs. Right now I only have access to Linux.
p.