new feature: if ctx==NULL in SSL_CTX_ctrl perform syntax checking only for some operations (currently curves and signature algorithms)

ssl/t1_lib.c

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 31b3bd7..952e9eb 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -525,6 +525,8 @@
 	ncb.nidcnt = 0;
 	if (!CONF_parse_list(str, ':', 1, nid_cb, &ncb))
 		return 0;
+	if (pext == NULL)
+		return 1;
 	return tls1_set_curves(pext, pextlen, ncb.nid_arr, ncb.nidcnt);
 	}
 /* For an EC key set TLS id and required compression based on parameters */
@@ -3754,6 +3756,8 @@
 	sig.sigalgcnt = 0;
 	if (!CONF_parse_list(str, ':', 1, sig_cb, &sig))
 		return 0;
+	if (c == NULL)
+		return 1;
 	return tls1_set_sigalgs(c, sig.sigalgs, sig.sigalgcnt, client);
 	}