box: Fix guards not working
The guards weren't working because we were accessing data inside the arguments before checking them. Postpone data access until after the guards.
0x00007ffff741203c in gtk_box_pack (box=box@entry=0x0, child=0xe0b1b0, expand=expand@entry=0, fill=fill@entry=0, padding=padding@entry=0, pack_type=pack_type@entry=GTK_PACK_START)
at /usr/src/debug/gtk3-3.24.28-2.fc34.x86_64/gtk/gtkbox.c:1530
1530 GtkBoxPrivate *private = box->priv;
(gdb) bt
#0 0x00007ffff741203c in gtk_box_pack (box=box@entry=0x0, child=0xe0b1b0, expand=expand@entry=0, fill=fill@entry=0, padding=padding@entry=0, pack_type=pack_type@entry=GTK_PACK_START)
at /usr/src/debug/gtk3-3.24.28-2.fc34.x86_64/gtk/gtkbox.c:1530
#1 0x00007ffff741223c in gtk_box_pack_start (box=box@entry=0x0, child=<optimized out>, expand=expand@entry=0, fill=fill@entry=0, padding=padding@entry=0)
at /usr/src/debug/gtk3-3.24.28-2.fc34.x86_64/gtk/gtkbox.c:2179