Let the TLSv1_method() etc. functions return a const SSL_METHOD
pointer and make the SSL_METHOD parameter in SSL_CTX_new,
SSL_CTX_set_ssl_version and SSL_set_ssl_method const.

ssl/t1_clnt.c

diff --git a/ssl/t1_clnt.c b/ssl/t1_clnt.c
index 4d1e198..c87af17 100644
--- a/ssl/t1_clnt.c
+++ b/ssl/t1_clnt.c
@@ -63,8 +63,8 @@
 #include <openssl/objects.h>
 #include <openssl/evp.h>
 
-static SSL_METHOD *tls1_get_client_method(int ver);
-static SSL_METHOD *tls1_get_client_method(int ver)
+static const SSL_METHOD *tls1_get_client_method(int ver);
+static const SSL_METHOD *tls1_get_client_method(int ver)
 	{
 	if (ver == TLS1_VERSION)
 		return(TLSv1_client_method());