Bug#566174: gtk apps set WM_COMMAND incorrectly on the leader window

[anomie]

I suppose it would help if I actually sent the testcase.

/* gcc -Wall foo.c -o foo `pkg-config --cflags --libs gtk+-2.0` */
#include <gtk/gtk.h>

int main(int argc, char **argv){
    g_set_prgname("this-will-be-wrong");
    gtk_init(&argc, &argv);
    gtk_widget_show(gtk_window_new(GTK_WINDOW_TOPLEVEL));
    gtk_main();
    return 0;
}