Add default return values to switch statements

We are using g_assert_not_reached() without doing anything, assuming it
aborts the program. In release builds however, it is ignored.

gdk/x11/gdkdevicemanager-core-x11.c

@@ -265,6 +265,7 @@ translate_crossing_mode (int mode)
       return GDK_CROSSING_UNGRAB;
     default:
       g_assert_not_reached ();
+      return GDK_CROSSING_NORMAL;
     }
 }
 
@@ -285,6 +286,7 @@ translate_notify_type (int detail)
       return GDK_NOTIFY_NONLINEAR_VIRTUAL;
     default:
       g_assert_not_reached ();
+      return GDK_NOTIFY_UNKONWN;
     }
 }
 

gdk/x11/gdkdevicemanager-xi2.c

@@ -1068,6 +1068,7 @@ translate_crossing_mode (gint mode)
       /* Fall through, unexpected in pointer crossing events */
     default:
       g_assert_not_reached ();
+      return GDK_CROSSING_NORMAL;
     }
 }
 
@@ -1088,6 +1089,7 @@ translate_notify_type (gint detail)
       return GDK_NOTIFY_NONLINEAR_VIRTUAL;
     default:
       g_assert_not_reached ();
+      return GDK_NOTIFY_UNKONWN;
     }
 }
 

gtk/gtkcssselector.c

@@ -876,6 +876,7 @@ change_pseudoclass_position (const GtkCssSelector *selector)
       return GTK_CSS_CHANGE_FIRST_CHILD | GTK_CSS_CHANGE_LAST_CHILD;
     default:
       g_assert_not_reached ();
+      return 0;
     }
 }
 

gtk/inspector/general.c

@@ -501,7 +501,7 @@ translate_subpixel_layout (GdkSubpixelLayout subpixel)
     case GDK_SUBPIXEL_LAYOUT_HORIZONTAL_BGR: return "horizontal bgr";
     case GDK_SUBPIXEL_LAYOUT_VERTICAL_RGB: return "vertical rgb";
     case GDK_SUBPIXEL_LAYOUT_VERTICAL_BGR: return "vertical bgr";
-    default: g_assert_not_reached ();
+    default: g_assert_not_reached (); return "none;
     }
 }