memory leak with gtk+-2.8.20-r1

[gwenhael <gwenjo free fr>]

Hello,
I use gtk+ for my soft's graphic interface.
But valgrind make an log file containing approximately 22700 lines for an
simple source code like : 
#include <gtk/gtk.h>

int main(int argc, char **argv) {
        gtk_init(&argc, &argv);
          GtkWidget *win= gtk_window_new(GTK_WINDOW_TOPLEVEL);
          g_signal_connect(G_OBJECT(win), "destroy", G_CALLBACK(gtk_main_quit), NULL);  
          gtk_widget_show_all(win);
          gtk_main();
          return EXIT_SUCCESS;
}
It's difficult to write more simple code...
I've made many searchs on the web but nothing information to resolve this problem.
I've recompiling all with : emerge -e world
downgrading all of X parts and gtk+ & glib. But the result are the same.
Visibly the big part of error are in gtk_init -> gdk_display_open and XOpenDisplay in libX11.
When the program is closed the display is not destroyed.
But the size of log to valgrind is very big (1.6M) and it's impossible to join with mail.
Someone has the same problem or an solution to solve this leak of memory? 
Thank you very much.

Gwenhaël