Bug#1150262: gtkmm: Compile error: conflicting declaration `using GdkCursorClass = struct _GdkCursorClass`

[Simon McVittie]

On Wed, 07 Oct 2026 at 20:53:58 +0200, Andre Offringa wrote:
>/usr/include/gtkmm-4.0/gdkmm/cursor.h:30:7: error: conflicting declaration
>‘using GdkCursorClass = struct _GdkCursorClass’
...
>/usr/include/gtk-4.0/gdk/gdkcursor.h:38:1: note: previous declaration as
>‘typedef struct GdkCursorClass GdkCursorClass’

This looks like an incompatibility between older gtkmm4.0 and newer 
GTK4. Please try upgrading libgtkmm-4.0-dev to the version from 
unstable.

     smcv