unix: add ioctlPtr with unsafe.Pointer arg on other unices (cont)

CL 469315 missed a few conversions, this CL adds them. While
here, also update syscall wrapper generators.

For golang/go#44834

Change-Id: I4418a8c177ee6d1a269c1cc2c806b199dc7ccf0b
Reviewed-on: https://go-review.googlesource.com/c/sys/+/471119
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Dmitri Goutnik <dgoutnik@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>

unix/syscall_hurd.go

@@ -20,3 +20,11 @@ func ioctl(fd int, req uint, arg uintptr) (err error) {
 	}
 	return
 }
+
+func ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) {
+	r0, er := C.ioctl(C.int(fd), C.ulong(req), C.uintptr_t(uintptr(arg)))
+	if r0 == -1 && er != nil {
+		err = er
+	}
+	return
+}