bugfix: fixed a compiliation error in the timer module when the DDEBUG macro is set to 1 or a C compiler without variadic macro support (like the Microsoft Visual C++ compiler) is used. thanks itpp16 for the patch in openresty#443.

Author: agentzh

src/ngx_http_lua_timer.c

@@ -475,7 +475,7 @@ ngx_http_lua_log_timer_error(ngx_log_t *log, u_char *buf, size_t len)
 
     c = log->data;
 
-    dd("ctx = %p", ctx);
+    dd("ctx = %p", c);
 
     p = ngx_snprintf(buf, len, ", context: ngx.timer");
     len -= p - buf;