Description:
------------
When dragging 3x from the window to itself, php crashes. You need to apply the GtkSelectionData get_uris/set_uris patch I sent to php-gtk-dev today first.

Reproduce code:
---------------
<?php
$wnd = new GtkWindow();
$wnd->connect_simple('destroy', array('Gtk', 'main_quit'));
$wnd->drag_source_set(Gdk::BUTTON1_MASK, array(), Gdk::ACTION_COPY);


$wnd->drag_source_set(
    Gdk::BUTTON1_MASK,
    array(array('text/uri-list', 0, 0)),
    Gdk::ACTION_COPY
);
$wnd->drag_dest_set(
    Gtk::DEST_DEFAULT_ALL,
    array(array('text/uri-list', 0, 0)),
    Gdk::ACTION_COPY
);
$wnd->drag_dest_add_uri_targets();

$wnd->connect('drag-data-get', 'onGetDragData');
$wnd->connect('drag-data-received', 'onDragDataReceived');


function onDragDataReceived($widget, $context, $x, $y, $data, $info, $time) {
    echo "drag-data-received\r\n";
    var_dump($data->get_uris());
}
function onGetDragData($widget, $context, $selection, $info, $time) {
    echo "drag-data-get\r\n";
//    $selection->set(Gdk::atom_intern('text/variable'), 8, 'abc', 3);
    $selection->set_uris(array('file:///', 'file:///home/cweiske/a.out'));
}


$wnd->show_all();
Gtk::main();
?>

Actual result:
--------------
*** glibc detected *** corrupted double-linked list: 0x08dd5e00 ***

Program received signal SIGABRT, Aborted.
[Switching to Thread 16384 (LWP 10903)]
0xb7bcc0b1 in kill () from /lib/libc.so.6
(gdb) bt
#0  0xb7bcc0b1 in kill () from /lib/libc.so.6
#1  0xb77631e1 in pthread_kill () from /lib/libpthread.so.0
#2  0xb776355b in raise () from /lib/libpthread.so.0
#3  0xb7bcbe44 in raise () from /lib/libc.so.6
#4  0xb7bcd30d in abort () from /lib/libc.so.6
#5  0xb7bfe5bc in __fsetlocking () from /lib/libc.so.6
#6  0xb7c08417 in mallopt () from /lib/libc.so.6
#7  0xb7c07465 in mallopt () from /lib/libc.so.6
#8  0xb7c06a91 in mallopt () from /lib/libc.so.6
#9  0xb7c05b33 in malloc () from /lib/libc.so.6
#10 0xb701f77e in cairo_matrix_invert () from /usr/lib/libcairo.so.2
#11 0x0000020c in ?? ()
#12 0x3fecfcfc in ?? ()
#13 0xb70519f4 in ?? () from /usr/lib/libcairo.so.2
#14 0xb701f61e in cairo_matrix_invert () from /usr/lib/libcairo.so.2
#15 0x08dd4e48 in ?? ()
#16 0x00000000 in ?? ()
#17 0xbffa5798 in ?? ()
#18 0xb709bdb9 in gdk_cairo_set_source_color ()
   from /usr/lib/libgdk-x11-2.0.so.0
#19 0x00fa5790 in ?? ()
#20 0x08dd5798 in ?? ()
#21 0x08dd5790 in ?? ()
---Type <return> to continue, or q <return> to quit---
#22 0xb701f31a in cairo_matrix_invert () from /usr/lib/libcairo.so.2
#23 0x08dd5798 in ?? ()
#24 0x00000000 in ?? ()
#25 0xbffa5770 in ?? ()
#26 0x00000001 in ?? ()
#27 0x00000000 in ?? ()
#28 0x00000000 in ?? ()
#29 0x00000000 in ?? ()
#30 0xb7013d8a in cairo_move_to () from /usr/lib/libcairo.so.2
#31 0x08dd5798 in ?? ()
#32 0x00000000 in ?? ()
#33 0x00000000 in ?? ()
#34 0x00000000 in ?? ()
#35 0x00000000 in ?? ()
#36 0x00000000 in ?? ()
#37 0x00000000 in ?? ()
#38 0x00000000 in ?? ()
#39 0xb70519f4 in ?? () from /usr/lib/libcairo.so.2
#40 0x08dd5790 in ?? ()
#41 0x08dcf148 in ?? ()
#42 0xb70144f0 in cairo_rectangle () from /usr/lib/libcairo.so.2
#43 0x08dd5790 in ?? ()
#44 0x00000000 in ?? ()
---Type <return> to continue, or q <return> to quit---
#45 0x00000000 in ?? ()
#46 0x00000000 in ?? ()
#47 0x00000000 in ?? ()
#48 0xb70519f4 in ?? () from /usr/lib/libcairo.so.2
#49 0x08dd5790 in ?? ()
#50 0xb701323a in cairo_create () from /usr/lib/libcairo.so.2
#51 0x00000000 in ?? ()
#52 0x40690000 in ?? ()
#53 0x00000000 in ?? ()
#54 0x40690000 in ?? ()
#55 0x08dd5790 in ?? ()
#56 0xb71090a8 in ?? () from /usr/lib/libgdk-x11-2.0.so.0
#57 0x08dd5790 in ?? ()
#58 0xb70b603e in gdk_window_get_internal_paint_info ()
   from /usr/lib/libgdk-x11-2.0.so.0
#59 0x00000000 in ?? ()