Add pointers to enforce lifetimes

        if ptr.is_null() {

            None

        } else {

            Some(X509 { x509: ptr })

            Some(X509 { ctx: self, x509: ptr })

        }

    }

}

/// A public key certificate

pub struct X509<'ctx> {

    priv ctx: &'ctx X509StoreContext,

    priv x509: *ffi::X509

}

impl<'ctx> X509<'ctx> {

    pub fn subject_name<'a>(&'a self) -> X509Name<'a> {

        let name = unsafe { ffi::X509_get_subject_name(self.x509) };

        X509Name { x509: self, name: name }

    }

}

pub struct X509Name<'x> {

    priv x509: &'x X509<'x>,

    priv name: *ffi::X509_NAME

}