stats: use GTimer instead of time(NULL)

time(NULL) shows the wrong results when the machine's clock is
changed.

src/main.c

@@ -350,6 +350,7 @@ int main(int argc, char *argv[])
 	songvec_deinit();
 	dirvec_deinit();
 	idle_deinit();
+	stats_global_finish();
 
 	close_log_files();
 	return EXIT_SUCCESS;

src/stats.c

@@ -29,7 +29,12 @@ struct stats stats;
 
 void stats_global_init(void)
 {
-	stats.start_time = time(NULL);
+	stats.timer = g_timer_new();
+}
+
+void stats_global_finish(void)
+{
+	g_timer_destroy(stats.timer);
 }
 
 struct visit_data {
@@ -107,7 +112,7 @@ int stats_print(struct client *client)
 		      stats.artist_count,
 		      stats.album_count,
 		      stats.song_count,
-		      time(NULL) - stats.start_time,
+		      (long)g_timer_elapsed(stats.timer, NULL),
 		      (long)(getPlayerTotalPlayTime() + 0.5),
 		      stats.song_duration,
 		      db_get_mtime());

src/stats.h

@@ -19,10 +19,12 @@
 #ifndef MPD_STATS_H
 #define MPD_STATS_H
 
+#include <glib.h>
+
 struct client;
 
 struct stats {
-	unsigned long start_time;
+	GTimer *timer;
 
 	/** number of song files in the music directory */
 	unsigned song_count;
@@ -42,6 +44,8 @@ extern struct stats stats;
 
 void stats_global_init(void);
 
+void stats_global_finish(void);
+
 void stats_update(void);
 
 int stats_print(struct client *client);