We should standarise on C comments.

ares/ares_expand_name.c

@@ -75,10 +75,11 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf,
   q = *s;
 
   if (len == 0) {
-    // RFC2181 says this should be ".": the root of the DNS tree.
-    // Since this function strips trailing dots though, it becomes ""
+    /* RFC2181 says this should be ".": the root of the DNS tree.
+     * Since this function strips trailing dots though, it becomes ""
+     */
     q[0] = '\0';
-    *enclen = 1;  // the caller should move one byte to get past this
+    *enclen = 1;  /* the caller should move one byte to get past this */
     return ARES_SUCCESS;
   }