On systems that have strlcat() and strlcpy() in libc, run the tests twice (once with our implementation and once with the system's) to verify that our tests are correct.
Not only is this a slightly more logical name, but it allows us to expose the verbose flag, previously private to cryb_t_main.c, as the equally logically named t_verbose.
POSIX requires <stdio.h> and <unistd.h> to define off_t and ssize_t like <sys/types.h> does, but not all platforms respect that. Play it safe by always including <sys/types.h>.
Instead of having libcryb-test provide main() and assume that the test program defines t_prepare() and t_cleanup(), have libcryb-test provide a t_main() function which the test program calls with pointers to its prepare and cleanup functions.
