Added a memory write boundary protection in the ram watch window to prevent users from writing into ROM memory area.

src/drivers/sdl/ramwatch.cpp

@@ -948,6 +948,8 @@ static void ramWatch_cell_edited_cb (GtkCellRendererText * cell,
 			break;
 		case 1:
 		case 2:
+		{
+			if ( (rw->addr >= 0) && (rw->addr < 0x8000) )
 			{
 				writefunc wfunc;
 
@@ -999,6 +1001,7 @@ static void ramWatch_cell_edited_cb (GtkCellRendererText * cell,
 					}
 				}
 			}
+		}
 			break;
 		case 3:
 			rw->name.assign (new_text);