From a fresh update of Tcl trunk (2017-05-29), compiled with default options:

% info hostname
cabernet.vinotinto.com.ar
% info patchlevel
8.7a0
% uname -a
NetBSD cabernet.vinotinto.com.ar 7.1 NetBSD 7.1 (GENERIC.201703111743Z) i386

So this ticket can be closed.

The issue of using non-standard interfaces (gethostbyname_r) when a standard one can be used (getaddrinfo) should be addressed to avoid reintroducing these type of
bugs