Resolve warnings in VC-WIN32 build, which allows to add /WX. It's argued that /WX allows to keep better focus on new code, which motivates its comeback... Reviewed-by: Rich Salz <rsalz@openssl.org> (Merged from https://github.com/openssl/openssl/pull/4721)

diff --git a/ssl/record/rec_layer_s3.c b/ssl/record/rec_layer_s3.c
index c1101a6..317719b 100644
--- a/ssl/record/rec_layer_s3.c
+++ b/ssl/record/rec_layer_s3.c

@@ -1417,7 +1417,7 @@
             memcpy(dest + *dest_len,
                    SSL3_RECORD_get_data(rr) + SSL3_RECORD_get_off(rr), n);
             SSL3_RECORD_add_off(rr, n);
-            SSL3_RECORD_add_length(rr, -n);
+            SSL3_RECORD_sub_length(rr, n);
             *dest_len += n;
             if (SSL3_RECORD_get_length(rr) == 0)
                 SSL3_RECORD_set_read(rr);

diff --git a/ssl/statem/extensions_clnt.c b/ssl/statem/extensions_clnt.c
index ff2e0cf..a690751 100644
--- a/ssl/statem/extensions_clnt.c
+++ b/ssl/statem/extensions_clnt.c

@@ -1316,7 +1316,7 @@
         OPENSSL_free(s->ext.scts);
         s->ext.scts = NULL;
 
-        s->ext.scts_len = size;
+        s->ext.scts_len = (uint16_t)size;
         if (size > 0) {
             s->ext.scts = OPENSSL_malloc(size);
             if (s->ext.scts == NULL

diff --git a/ssl/statem/statem_lib.c b/ssl/statem/statem_lib.c
index 6db8816..cb1fb7d 100644
--- a/ssl/statem/statem_lib.c
+++ b/ssl/statem/statem_lib.c

@@ -2020,7 +2020,7 @@
 
     /* Inject the synthetic message_hash message */
     msghdr[0] = SSL3_MT_MESSAGE_HASH;
-    msghdr[SSL3_HM_HEADER_LENGTH - 1] = hashlen;
+    msghdr[SSL3_HM_HEADER_LENGTH - 1] = (unsigned char)hashlen;
     if (!ssl3_finish_mac(s, msghdr, SSL3_HM_HEADER_LENGTH)
             || !ssl3_finish_mac(s, hashval, hashlen)) {
         SSLerr(SSL_F_CREATE_SYNTHETIC_MESSAGE_HASH, ERR_R_INTERNAL_ERROR);

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 48f01ff..c1db7df 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c

@@ -199,7 +199,7 @@
     size_t i;
     for (i = 0; i < OSSL_NELEM(nid_list); i++) {
         if (nid_list[i].nid == nid)
-            return i + 1;
+            return (uint16_t)(i + 1);
     }
     return 0;
 }