Wrong result of MAKETIME(0, 0, -0.1)

There is some inconsistency between
MAKETIME(0,0, negative_integer_number) and
MAKETIME(0,0, negative_decimal_number)

SELECT MAKETIME(0,0,-1), MAKETIME(0, 0, -0.1);

+------------------+----------------------+

| MAKETIME(0,0,-1) | MAKETIME(0, 0, -0.1) |

+------------------+----------------------+

| NULL             | 00:00:00             |

+------------------+----------------------+

The expression with the negative decimal number should also return NULL.

MySQL-5.5 exhibits the same behaviour.
MySQL-5.6 returns NULL for both expressions.