strcmp and strncmp weird behavior

[capitanpiluso]

The testfile is behaving really weirdly.
The outputs of the standard library's strcmp is always 1, -1 or 0.
The testfile is somehow failing at the comparison.

For example, the difference between "a" and "z"
strcmp returns -1 and my ft_strcmp returns -1 as well, and yet your testfile fails me.

But other people's ft_strcmp returns a difference instead, so somehow your testfile passes the following values: (again, comparing "a" and "z")
strcmp returns -1 and other people's ft_strcmp returns -25, and yet your testfile passes them.

I checked the logic in 1266 and 1199 and seems to be fine, but somehow it is behaving weirdly.
Where is the Maintest getting its string.h?