Direct syscalls using syscall numbers are no longer supported on darwin
since Go 1.12, see https://golang.org/doc/go1.12#darwin. Also,
/usr/include/sys/syscall.h is no longer available on recent macOS
versions, so remove the generating script.
Change-Id: I8e2579c3d0e94a61fc041d06280149ec6ccf13e2
Reviewed-on: https://go-review.googlesource.com/c/go/+/257638
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>