Sessionsetup.c is reporting the server OS as "Unix". Can this be changed to default to "Unix", but allow the config.h file to override? In the 2.2.x stream and earlier this is in reply.c, and on those streams the VMS port of SAMBA has been reporting "OpenVMS" through a conditional compile.
Do people other than smbclient users see or worry about this string? I don't think this should be a config.h or smb.conf parameter though. If you write a patch to allow the string to be set using include/local.h I will most likely apply it.
I am not sure if the native Microsoft tools can display this information. I thought that it showed up on some of them, but it has been 3 years since I have used them in that capacity. Every SAMBA-VMS port that I can find has had this hack in one way or another. I do not know why it was done in the first place. :-) Currently the VMS ports use the SAMBA supplied local.h file with no changes. Is this file generated/modified by something in the UNIX build? Right now I am getting the J.Y.C. VMS port of 2.2.8 up to 2.2.12, and using this to find what VMS specific changes have been made, and what are likely still going to be needed for the 3.x and 4.x streams after VMS specific VFS modules are written.
local.h is for things that are constant 99% of the time but that you might like to change for some specific reason. It's not touched by any of the build system so it needs to be tweaked by hand. Personally, I haven't seen any tools that display any of the protocol information at that level.