Portability problems not fixed by Gnulib:
@itemize
@item
+This function's second argument type is @code{int} instead of @code{size_t}
+on some platforms:
+OSF/1 5.1, Solaris 10.
+@item
If the given buffer is too small for the host name, some implementations
fail with @code{EINVAL}, instead of returning a truncated host name.
@end itemize