nginx-1.11.5-heroku.patch

--- src/http/modules/ngx_http_log_module.c.heroku	2016-10-12 02:03:02.000000000 +1100
+++ src/http/modules/ngx_http_log_module.c	2016-10-19 12:14:15.000000000 +1100
@@ -1207,7 +1207,13 @@
     n = ngx_http_script_variables_count(&value[1]);

     if (n == 0) {
-        log->file = ngx_conf_open_file(cf->cycle, &value[1]);
+        name = value[1];
+
+        if (ngx_strcmp(value[1].data, "error") == 0) {
+            ngx_str_null(&name);
+        }
+
+        log->file = ngx_conf_open_file(cf->cycle, &name);
         if (log->file == NULL) {
             return NGX_CONF_ERROR;
         }