Co-Authored-By: gnzlbg <gnzlbg@users.noreply.github.com>

Add a new feature to enable this, since `const extern fn`
support is unstable

adding PATH_MAX

use type c_int for _PARM_NAME_MAX and _PARM_PATH_MAX

See
https://github.com/torvalds/linux/blob/54ecb8f7/include/uapi/linux/if_link.h#L354-L362

It's *msg_prio* in both manpages and posix.

defining uintptr_t = usize and intptr_t/ptrdiff_t = isize, and using uintptr_t to define size_t, and intptr_t to define ssize_t.

2. implement Debug for big size array
3. remove code related to epoll
4. use 'pub enum' for _Vx_semaphore

This adds libc-test support for Freebsd10 and a CI build job that tests
FreeBSD10 with LIBC_CI only.