All //sys instructions moved to separate syscall_* files

Generated `syscall_*` files ranamed to `zsyscall_*` ones
like it done in `golang.org/x/sys` package.

zsyscall_freebsd.go

@@ -0,0 +1,21 @@
+//
+// Copyright 2014-2016 Cristian Maglie. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+
+// This file is machine generated by the command:
+//   mksyscall.pl serial_darwin.go
+// The generated stub is modified to make it compile under the "serial" package
+
+package serial // import "go.bug.st/serial.v1"
+
+import "syscall"
+
+func ioctl(fd int, req uint64, data uintptr) (err error) {
+	_, _, e1 := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), uintptr(req), uintptr(data))
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}