GOB: Mark intentional fallthrough in switch statements

engines/gob/draw_v2.cpp

@@ -562,6 +562,7 @@ void Draw_v2::printTotText(int16 id) {
 
 		default:
 			str[strPos] = (char) cmd;
+			// fall through
 		case 32:
 			mask[strPos++] = maskChar;
 			ptr++;

engines/gob/expression.cpp

@@ -153,7 +153,7 @@ void Expression::skipExpr(char stopToken) {
 
 			case 15:
 				_vm->_game->_script->skip(2);
-
+				// fall through
 			case OP_ARRAY_INT8:
 			case OP_ARRAY_INT32:
 			case OP_ARRAY_INT16:

engines/gob/minigames/geisha/oko.cpp

@@ -79,6 +79,7 @@ void Oko::advance() {
 		case kStateBreathe:
 			if ((getFrame() == 6) || (getFrame() == 23))
 				_sound->blasterPlay(_breathe, 1, 0);
+			// fall through
 		case kStateSink:
 		case kStateRaise:
 		case kStateHurt: