arc4random.c: In the incredibly unbelievable circumstance where
_rs_init() fails to allocate pages, don't call abort() because of
corefile data leakage concerns, but simply _exit(). The reasoning
is _rs_init() will only fail if someone finds a way to apply
specific pressure against this failure point, for the purpose of
leaking information into a core which they can read. We don't
need a corefile in this instance to debug that. So take this
"lever" away from whoever in the future wants to do that.
arc4random.3: reference random(4)
arc4random_uniform.c: include stdint.h over sys/types.h
It is a useful arc4random wrapper in the kernel for much the same reasons as
in userspace. Move the source to libkern (because kernel build is
restricted to sys/, but userspace can include any file it likes) and build
kernel and libc versions from the same source file.
Copy the documentation from arc4random_uniform(3) to the section 9 page.
While here, add missing arc4random_buf(9) symlink.
Sponsored by: Dell EMC Isilon
