Cleanse memory using the new OPENSSL_cleanse() function.
I've covered all the memset()s I felt safe modifying, but may have missed some.

ssl/s3_enc.c

diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
index cec8fcd..35fde29 100644
--- a/ssl/s3_enc.c
+++ b/ssl/s3_enc.c
@@ -182,7 +182,7 @@
 
 		km+=MD5_DIGEST_LENGTH;
 		}
-	memset(smd,0,SHA_DIGEST_LENGTH);
+	OPENSSL_cleanse(smd,SHA_DIGEST_LENGTH);
 	EVP_MD_CTX_cleanup(&m5);
 	EVP_MD_CTX_cleanup(&s1);
 	return 1;
@@ -333,8 +333,8 @@
 
 	EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
 
-	memset(&(exp_key[0]),0,sizeof(exp_key));
-	memset(&(exp_iv[0]),0,sizeof(exp_iv));
+	OPENSSL_cleanse(&(exp_key[0]),sizeof(exp_key));
+	OPENSSL_cleanse(&(exp_iv[0]),sizeof(exp_iv));
 	EVP_MD_CTX_cleanup(&md);
 	return(1);
 err:
@@ -408,7 +408,7 @@
 	{
 	if (s->s3->tmp.key_block != NULL)
 		{
-		memset(s->s3->tmp.key_block,0,
+		OPENSSL_cleanse(s->s3->tmp.key_block,
 			s->s3->tmp.key_block_length);
 		OPENSSL_free(s->s3->tmp.key_block);
 		s->s3->tmp.key_block=NULL;