cmocka 0.2.0

The idea of CMocka is that a test application only requires the standard C
library and CMocka itself to minimize the conflicts with standard C library
headers especially on a lot of different platforms. It is a fork of cmockery
(also in homebrew) which is not maintained anymore.

Closes #17092.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>