func convertToPolicyParaType(p unsafe.Pointer) syscall.Pointer {
	return (syscall.Pointer)(p)
}
For Go versions >= 1.11, the ExtraPolicyPara field in
syscall.CertChainPolicyPara is of type syscall.Pointer.  See:
https://github.com/golang/go/commit/4869ec00e87ef
package x509
import (
	"syscall"
	"unsafe"
)