Silence UBSan dynamic-type-mismatch for VclPtr member in GObject

...that wasn't properly initialized (in an --enable-dbgutil build; see also
<https://gerrit.libreoffice.org/c/core/+/117878> "There appears to be no reason
for (DBG_UTIL-only) ~VclPtr to be virtual", but even when VclPtr has no vtable,
it arguably is to properly con- and destruct CustomCellRendererSurface::device).

For example, in Writer clicking on the "Styles" icon in the side bar:

> vcl/unx/gtk3/gtkinst.cxx:15144:10: runtime error: member call on address 0x625001b42668 which does not point to an object of type 'VclPtr<VirtualDevice>'
> 0x625001b42668: note: object has invalid vptr
>  50 62 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  10 8a f0 00 30 60 00 00  80 f8 19 02
>               ^~~~~~~~~~~~~~~~~~~~~~~
>               invalid vptr
>  #0 in (anonymous namespace)::ensure_device((anonymous namespace)::CustomCellRendererSurface*, weld::Widget*) at vcl/unx/gtk3/gtkinst.cxx:15144:10

Change-Id: Ic6ab75668e5b3ecca6d1e5743ed1907c8cbdb143
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/117915
Tested-by: Jenkins
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

0 files changed, 0 insertions, 0 deletions