Squash more warnings

src/base64.c

@@ -31,7 +31,7 @@ static int mg_b64rev(int c) {
 }
 
 int mg_base64_update(unsigned char ch, char *to, int n) {
-  unsigned char rem = (n & 3) % 3;
+  int rem = (n & 3) % 3;
   if (rem == 0) {
     to[n] = (char) mg_b64idx(ch >> 2);
     to[++n] = (char) ((ch & 3) << 4);

src/dns.c

@@ -83,7 +83,7 @@ size_t mg_dns_parse_rr(const uint8_t *buf, size_t len, size_t ofs,
   if (s > e) return 0;
   rr->atype = (uint16_t)(((uint16_t) s[-4] << 8) | s[-3]);
   rr->aclass = (uint16_t)(((uint16_t) s[-2] << 8) | s[-1]);
-  if (is_question) return rr->nlen + 4;
+  if (is_question) return (size_t)(rr->nlen + 4);
 
   s += 6;
   if (s > e) return 0;
@@ -244,7 +244,7 @@ static void mg_sendnsreq(struct mg_connection *c, struct mg_str *name, int ms,
 #if MG_ENABLE_LOG
     char buf[100];
 #endif
-    d->txnid = s_reqs ? s_reqs->txnid + 1 : 1;
+    d->txnid = s_reqs ? (uint16_t)(s_reqs->txnid + 1) : 1;
     d->next = s_reqs;
     s_reqs = d;
     d->expire = mg_millis() + (unsigned long) ms;

src/mqtt.c

@@ -119,7 +119,7 @@ int mg_mqtt_parse(const uint8_t *buf, size_t len, struct mg_mqtt_message *m) {
   memset(m, 0, sizeof(*m));
   m->dgram.ptr = (char *) buf;
   if (len < 2) return MQTT_INCOMPLETE;
-  m->cmd = buf[0] >> 4;
+  m->cmd = (uint8_t)(buf[0] >> 4);
   m->qos = (buf[0] >> 1) & 3;
 
   n = len_len = 0;