Fixed build on MSVC.

src/core/ngx_inet.c

diff --git a/src/core/ngx_inet.c b/src/core/ngx_inet.c
index b5c57b7..873bf73 100644
--- a/src/core/ngx_inet.c
+++ b/src/core/ngx_inet.c
@@ -590,13 +590,13 @@
 #if (NGX_HAVE_INET6)
     case AF_INET6:
         sin6 = (struct sockaddr_in6 *) addr->sockaddr;
-        sin6->sin6_port = htons(port);
+        sin6->sin6_port = htons((in_port_t) port);
         break;
 #endif
 
     default: /* AF_INET */
         sin = (struct sockaddr_in *) addr->sockaddr;
-        sin->sin_port = htons(port);
+        sin->sin_port = htons((in_port_t) port);
         break;
     }