merge r3185:

fix building by gcc45
diff --git a/src/http/modules/ngx_http_rewrite_module.c b/src/http/modules/ngx_http_rewrite_module.c
index f7c138d..1f98cf8 100644
--- a/src/http/modules/ngx_http_rewrite_module.c
+++ b/src/http/modules/ngx_http_rewrite_module.c
@@ -446,7 +446,7 @@
             return NGX_CONF_ERROR;
         }
 
-        *code = (uintptr_t) NULL;
+        *code = NULL;
     }
 
     regex->next = (u_char *) lcf->codes->elts + lcf->codes->nelts