knot: patch enabling PKCS11 related code only if PKCS11 is available

Signed-off-by: Jan Hák <jan.hak@nic.cz>

net/knot/patches/03_libdnssec_pkcs11_support.patch

@@ -0,0 +1,17 @@
+--- a/src/libdnssec/key/key.c
++++ b/src/libdnssec/key/key.c
+@@ -146,10 +146,14 @@ dnssec_key_t *dnssec_key_dup(const dnsse
+ 
+ 		gnutls_privkey_type_t type = gnutls_privkey_get_type(key->private_key);
+ 		if (type == GNUTLS_PRIVKEY_PKCS11) {
++#ifdef ENABLE_PKCS11
+ 			gnutls_pkcs11_privkey_t tmp;
+ 			gnutls_privkey_export_pkcs11(key->private_key, &tmp);
+ 			gnutls_privkey_import_pkcs11(dup->private_key, tmp,
+ 			                             GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE);
++#else
++			assert(0);
++#endif
+ 		} else {
+ 			assert(type == GNUTLS_PRIVKEY_X509);
+ 			gnutls_x509_privkey_t tmp;