--- pidgin-otr-4.0.2/otr-plugin.c
+++ pidgin-otr-4.0.2/otr-plugin.c
@@ -39,6 +39,7 @@
 #include "util.h"
 #include "debug.h"
 #include "core.h"
+#include <libpurple/debug.h>
 
 #ifdef USING_GTK
 /* purple GTK headers */