libbb: introduce and use xgettimeofday(), do not truncate 64-bit time_t in shells

function                                             old     new   delta
xgettimeofday                                          -      11     +11
get_local_var_value                                  280     281      +1
svlogd_main                                         1323    1322      -1
change_epoch                                          67      66      -1
timestamp_and_log                                    461     458      -3
hwclock_main                                         301     298      -3
fmt_time_bernstein_25                                135     132      -3
step_time                                            331     326      -5
script_main                                         1207    1202      -5
machtime                                              34      28      -6
curtime                                               61      54      -7
ts_main                                              423     415      -8
nmeter_main                                          761     751     -10
gettime1900d                                          67      46     -21
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/12 up/down: 12/-73)           Total: -61 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/traceroute.c b/networking/traceroute.c
index 3f1a9ab..bd63e44 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -505,7 +505,7 @@
 		struct outdata6_t *pkt = (void *) outdata;
 		pkt->ident6 = ident;
 		pkt->seq6   = htonl(seq);
-		/*gettimeofday(&pkt->tv, &tz);*/
+		/*xgettimeofday(&pkt->tv);*/
 		icp = outicmp6;
 	} else
 #endif