resolv: Call gmtime_r instead of gmtime in p_secstodate [BZ #20017]

ChangeLog

@@ -1,3 +1,9 @@
+2016-05-10  Florian Weimer  <fweimer@redhat.com>
+
+	[BZ #20017]
+	* resolv/res_debug.c (p_secstodate): Call __gmtime_r instead of
+	gmtime.
+
 2016-05-10  Florian Weimer  <fweimer@redhat.com>
 
 	[BZ #19994]

resolv/res_debug.c

@@ -1035,13 +1035,8 @@ p_secstodate (u_long secs) {
 	time_t clock = secs;
 	struct tm *time;
 
-#ifdef HAVE_TIME_R
 	struct tm timebuf;
-
+	time = __gmtime_r(&clock, &timebuf);
-	time = gmtime_r(&clock, &timebuf);
-#else
-	time = gmtime(&clock);
-#endif
 	time->tm_year += 1900;
 	time->tm_mon += 1;
 	sprintf(output, "%04d%02d%02d%02d%02d%02d",