inet_ntop.3: ATTRIBUTES: Note function that is thread-safe

The marking matches glibc marking.
The marking of functions in glibc is:
- inet_ntop: MT-Safe locale

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man3/inet_ntop.3

@@ -97,6 +97,19 @@ was not a valid address family.
 .B ENOSPC
 The converted address string would exceed the size given by
 .IR size .
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lb lb lb
+l l l.
+Interface	Attribute	Value
+T{
+.BR inet_ntop ()
+T}	Thread safety	MT-Safe locale
+.TE
+
 .SH CONFORMING TO
 POSIX.1-2001.
 Note that RFC\ 2553 defines a prototype where the last argument