Port lib/libc/ssp to FreeBSD

In most cases, the buffers and data were resized, but when dealing with the
helpers, some of the code was adjusted to fail more reliably

Submitted by: pho


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274066 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
rpc_control on FreeBSD is a public-ish API (not prefixed with __), not private
like NetBSD

Submitted by: pho


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274067 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f