diff --git a/include/proto/filters.h b/include/proto/filters.h
index 3deb2d1..1ca47c7 100644
--- a/include/proto/filters.h
+++ b/include/proto/filters.h
@@ -33,6 +33,7 @@
 extern const char *http_comp_flt_id;
 extern const char *cache_store_flt_id;
 extern const char *spoe_filter_id;
+extern const char *fcgi_flt_id;
 
 #define FLT_ID(flt)   (flt)->config->id
 #define FLT_CONF(flt) (flt)->config->conf