X509_REQ_check_private_key() is equivalent to X509_check_private_key()
except that B<x> represents a certificate request of structure B<X509_REQ>.
-=head1 RETURN VALUE
+=head1 RETURN VALUES
X509_check_private_key() and X509_REQ_check_private_key() return 1 if
the keys match each other, and 0 if not.