Strip c-style void in function defs

This was never needed for c++.

src/gnudiff_diff.h

@@ -318,9 +318,9 @@ struct change *find_change (struct change *);
 struct change *find_reverse_change (struct change *);
 void *zalloc (size_t);
 enum changes analyze_hunk (struct change *, LineRef *, LineRef *, LineRef *, LineRef *);
-void begin_output (void);
+void begin_output ();
 void debug_script (struct change *);
-void finish_output (void);
+void finish_output ();
 void message (const QChar *, const QChar *, const QChar *);
 void message5 (const QChar *, const QChar *, const QChar *, const QChar *, const QChar *);
 void output_1_line (const QChar *, const QChar *, const QChar *, const QChar *);
@@ -348,7 +348,7 @@ private:
    // gnudiff_xmalloc.cpp
    void *xmalloc (size_t n);
    void *xrealloc(void *p, size_t n);
-   void xalloc_die (void);
+   void xalloc_die ();
 
    inline bool isWhite( QChar c )
    {

src/gnudiff_xmalloc.cpp

@@ -30,9 +30,9 @@
 
 #include "gnudiff_diff.h"
 /* If non NULL, call this function when memory is exhausted. */
-void (*xalloc_fail_func)(void) = nullptr;
+void (*xalloc_fail_func)() = nullptr;
 
-void GnuDiff::xalloc_die(void)
+void GnuDiff::xalloc_die()
 {
     if(xalloc_fail_func)
         (*xalloc_fail_func)();

src/optiondialog.h

@@ -47,7 +47,7 @@ class OptionDialog : public KPageDialog
 public:
 
     explicit OptionDialog( bool bShowDirMergeSettings, QWidget *parent = nullptr );
-    ~OptionDialog( void ) override;
+    ~OptionDialog() override;
     QString parseOptions( const QStringList& optionList );
     QString calcOptionHelp();
 
@@ -61,9 +61,9 @@ public:
     void addOptionItem(OptionItemBase*);
     KKeyDialog* m_pKeyDialog;
 protected Q_SLOTS:
-    virtual void slotDefault( void );
-    virtual void slotOk( void );
-    virtual void slotApply( void );
+    virtual void slotDefault();
+    virtual void slotOk();
+    virtual void slotApply();
     //virtual void buttonClicked( QAbstractButton* );
     virtual void helpRequested();