Problem:

The ngroups variable in struct connection_struct is defined as size_t in include/smb.h

It's only usage is in smbd/service.c as the second parameter in a call:

       get_current_groups(conn->gid, &conn->ngroups,&conn->groups);

however, the prototype of the get_current_groups function (smbd/sec_ctx.c) declares arg2 to be int *.

On some platforms (eg: OSF1) size_t is not an int (it's 8 bytes, not 4).  This produces a compile warning.  It may produce runtime errors.

Solution:
Change include/smb.h to declare ngroups to be int.