Fix GC bug in FXAccelTable

The target objects stored in the accelerator table are currently
private. Therefore FXRbAccelTable::markfunc() doesn't mark them as used.
As a workaround the objects are additionally stored in @targets Hash.

ext/fox16/markfuncs.cpp

@@ -42,6 +42,7 @@ static void delete_if_not_owned_by_app(BASECLASS* self,SUBCLASS*){
 
 // FIXME: How to get to the target objects stored in the accelerator
 // table? This is currently private (not protected) data for the class.
+// See workaround in lib/fox16/accel_table.rb.
 void FXRbAccelTable::markfunc(FXAccelTable* accelTable){
   FXRbObject::markfunc(accelTable);
   }

lib/fox16/accel_table.rb

@@ -64,7 +64,20 @@ module Fox
           end
         end
       end
+      # FIXME: The target objects stored in the accelerator table are currently
+      # private. Therefore FXRbAccelTable::markfunc() doesn't mark them as used.
+      # As a workaround the objects are additionally stored in @targets Hash.
+      @targets = {} unless instance_variable_defined?('@targets')
+      @targets[hotKey] = tgt
       addAccelOrig(hotKey, tgt, seldn, selup)
     end
+
+    alias removeAccelOrig removeAccel # :nodoc:
+
+    def removeAccel(hotKey)
+      @targets = {} unless instance_variable_defined?('@targets')
+      @targets.delete(hotKey)
+      removeAccelOrig(hotKey)
+    end
   end
 end
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