Broadway GDK backend crashes Emacs

[Michał J. Gajda]

Running Emacs with Broadway GDK backend crashes Emacs:

```
$ GDK_BACKEND=broadway emacs-gtk
Fatal error 11: Segmentation fault
Backtrace:
emacs-gtk(+0x159f87)[0x5609b885df87]
emacs-gtk(+0x4ce13)[0x5609b8750e13]
emacs-gtk(+0x4d2f6)[0x5609b87512f6]
emacs-gtk(+0x158208)[0x5609b885c208]
emacs-gtk(+0x15828d)[0x5609b885c28d]
/lib/x86_64-linux-gnu/libc.so.6(+0x3c4b0)[0x7ff5c363c4b0]
/lib/x86_64-linux-gnu/libc.so.6(+0x173b1d)[0x7ff5c3773b1d]
emacs-gtk(+0x11d111)[0x5609b8821111]
emacs-gtk(+0x12039b)[0x5609b882439b]
emacs-gtk(+0x1c068b)[0x5609b88c468b]
emacs-gtk(+0x1ff57c)[0x5609b890357c]
emacs-gtk(+0x1c063f)[0x5609b88c463f]
emacs-gtk(+0x1c2990)[0x5609b88c6990]
emacs-gtk(+0x1c068b)[0x5609b88c468b]
emacs-gtk(+0x1ff57c)[0x5609b890357c]
emacs-gtk(+0x1c063f)[0x5609b88c463f]
/usr/bin/../lib/emacs/28.2/native-lisp/28.2-521777fc/preloaded/startup-bbc6ea72-3595433d.eln(F636f6d6d616e642d6c696e65_command_line_0+0x11b6)[0x7ff5bf34ba56]
emacs-gtk(+0x1c068b)[0x5609b88c468b]
/usr/bin/../lib/emacs/28.2/native-lisp/28.2-521777fc/preloaded/startup-bbc6ea72-3595433d.eln(F6e6f726d616c2d746f702d6c6576656c_normal_top_level_0+0xf9d)[0x7ff5bf3483bd]
emacs-gtk(+0x1c30dd)[0x5609b88c70dd]
emacs-gtk(+0x1c4cac)[0x5609b88c8cac]
emacs-gtk(+0x1bf5e7)[0x5609b88c35e7]
emacs-gtk(+0x13fdfa)[0x5609b8843dfa]
emacs-gtk(+0x1bf529)[0x5609b88c3529]
emacs-gtk(+0x13f0af)[0x5609b88430af]
emacs-gtk(+0x144cff)[0x5609b8848cff]
emacs-gtk(+0x145069)[0x5609b8849069]
emacs-gtk(+0x55772)[0x5609b8759772]
/lib/x86_64-linux-gnu/libc.so.6(+0x23a90)[0x7ff5c3623a90]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x89)[0x7ff5c3623b49]
emacs-gtk(+0x55e35)[0x5609b8759e35]
Segmentation fault (core dumped)
```

[Michał J. Gajda (mgajda)]

Please note that current Git HEAD works with `GDK_BACKEND=broadway`.