[Warning] Deprecated GtkStyle needs update

[jopadan]

SLADE Version

No response

OS

Windows, macOS, Linux

Issue Details

/usr/src/engines/editor/SLADE/jopadan/SLADE/src/OpenGL/Drawing.cpp: In function ‘wxColour slade::drawing::systemPanelBGColour()’:
/usr/src/engines/editor/SLADE/jopadan/SLADE/src/OpenGL/Drawing.cpp:564:51: warning: ‘GtkStyle* gtk_rc_get_style(GtkWidget*)’ is deprecated: Use 'GtkStyleContext' instead [-Wdeprecated-declarations]
  564 |                 GtkStyle*  def  = gtk_rc_get_style(menu);
      |                                   ~~~~~~~~~~~~~~~~^~~~~~
In file included from /usr/include/gtk-3.0/gtk/gtk.h:273,
                 from /usr/src/engines/editor/SLADE/jopadan/SLADE/src/OpenGL/Drawing.cpp:43:
/usr/include/gtk-3.0/gtk/deprecated/gtkrc.h:175:11: note: declared here
  175 | GtkStyle* gtk_rc_get_style              (GtkWidget   *widget);
      |           ^~~~~~~~~~~~~~~~
/usr/src/engines/editor/SLADE/jopadan/SLADE/src/OpenGL/Drawing.cpp:566:59: warning: ‘GtkStyle* gtk_widget_get_default_style()’ is deprecated: Use 'gtk_style_context_new' instead [-Wdeprecated-declarations]
  566 |                         def = gtk_widget_get_default_style();
      |                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
In file included from /usr/include/gtk-3.0/gtk/gtk.h:277:
/usr/include/gtk-3.0/gtk/deprecated/gtkstyle.h:774:12: note: declared here
  774 | GtkStyle*  gtk_widget_get_default_style   (void);
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~