Add internal_sysctl() used by FreeBSD, NetBSD, OpenBSD and MacOSX
Summary:
Switch local sysctl(2) calls to internal_sysctl().
This is a preparation for introduction of interceptors for
the sysctl*() family of functions and switching `internal_sysctl*()`
to libc calls bypassing interceptors.
No functional change intended with this revision.
Reviewers: vitalybuka, joerg, kcc
Reviewed By: vitalybuka
Subscribers: kubamracek, llvm-commits, #sanitizers
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D51425
llvm-svn: 341181