- 2: colormap
- 2: use_gc self-check (should be in USE_GC macro?)
- 2: ghid_gl_init_render; gtk4: gtk_gl_area_set_has_stencil_buffer
- 2: ghid_gl_init_drawing_widget
- 2: ghid_gl_start_drawing
- 2: ghid_gl_end_drawing
- 2: ghid_gl_port_drawing_realize
- 2: ghid_gl_new_drawing_widget
