--- a/src/internfile/internfile.h
+++ b/src/internfile/internfile.h
@@ -120,6 +120,11 @@
      */
     FileInterner(const Rcl::Doc& idoc, RclConfig *cnf, TempDir &td, 
                  int flags);
+
+    /** 
+     * Build sig for doc coming from rcldb. This is here because we know how
+     * to query the right backend */
+    static bool makesig(const Rcl::Doc& idoc, string& sig);
 
     ~FileInterner();