Fix some compiler warnings (unused function parameters)

Signed-off-by: Stefan Weil <sw@weilnetz.de>

dict/dawg.h

@@ -183,13 +183,20 @@ class Dawg {
   /// of the given unichar_id.
   virtual void unichar_id_to_patterns(UNICHAR_ID unichar_id,
                                       const UNICHARSET &unicharset,
-                                      GenericVector<UNICHAR_ID> *vec) const {};
+                                      GenericVector<UNICHAR_ID> *vec) const {
+    (void)unichar_id;
+    (void)unicharset;
+    (void)vec;
+  }
 
   /// Returns the given EDGE_REF if the EDGE_RECORD that it points to has
   /// a self loop and the given unichar_id matches the unichar_id stored in the
   /// EDGE_RECORD, returns NO_EDGE otherwise.
   virtual EDGE_REF pattern_loop_edge(
       EDGE_REF edge_ref, UNICHAR_ID unichar_id, bool word_end) const {
+    (void)edge_ref;
+    (void)unichar_id;
+    (void)word_end;
     return false;
   }
 

dict/dict.h

@@ -374,6 +374,7 @@ class Dict {
   double def_probability_in_context(
       const char* lang, const char* context, int context_bytes,
       const char* character, int character_bytes) {
+    (void) lang;
     (void) context;
     (void) context_bytes;
     (void) character;

viewer/scrollview.h

@@ -89,7 +89,7 @@ class SVEventHandler {
 
 // Gets called by the SV Window. Does nothing on default, overwrite this
 // to implement the desired behaviour
-    virtual void Notify(const SVEvent* sve) { }
+    virtual void Notify(const SVEvent* sve) { (void)sve; }
 };
 
 // The ScrollView class provides the expernal API to the scrollviewer process.