Fix compiler warnings mit gcc.

ChangeLog

@@ -1,3 +1,11 @@
+2020-08-06 Fred Kiefer <FredKiefer@gmx.de>
+
+	* Source/GSStoryboardTransform.h,
+	* Source/NSPageController.m,
+	* Source/NSPersistentDocument.m,
+	* Source/NSSplitViewItem.m,
+	* Source/NSViewController.m: Fix compiler warnings mit gcc.
+
 2020-07-31 Gregory John Casamento <greg.casamento@gmail.com>
 
 	* Headers/AppKit/AppKit.h: Add header

Source/GSStoryboardTransform.h

@@ -56,6 +56,8 @@ extern "C" {
 - (NSMapTable *) segueMapForIdentifier: (NSString *)identifier;
 
 - (void) processStoryboard: (NSXMLDocument *)storyboardXml;
+- (void) processSegues: (NSXMLDocument *)xml
+       forControllerId: (NSString *)identifier;
 @end
 
 // Private classes used when parsing the XIB generated by the transformer...

Source/NSPageController.m

@@ -97,12 +97,12 @@
   _transitionStyle = style;
 }
 
-- (id<NSPageControllerDelegate>) delegate
+- (id) delegate
 {
   return _delegate;
 }
 
-- (void) setDelegate: (id<NSPageControllerDelegate>)delegate
+- (void) setDelegate: (id)delegate
 {
   _delegate = delegate;
 }

Source/NSPersistentDocument.m

@@ -34,6 +34,11 @@ static Class persistentDocumentClass = nil;
 
 @implementation NSPersistentDocument
 
++ (void) setPersistentDocumentClass: (Class)clz
+{
+  persistentDocumentClass = clz;
+}
+
 + (void) initialize
 {
   if (self == [NSPersistentDocument class])
@@ -43,11 +48,6 @@ static Class persistentDocumentClass = nil;
     }
 }
 
-+ (void) setPersistentDocumentClass: (Class)clz
-{
-  persistentDocumentClass = clz;
-}
-
 + (id) allocWithZone: (NSZone *)z
 {
   if (persistentDocumentClass == self)

Source/NSSplitViewItem.m

@@ -24,6 +24,7 @@
 
 #import <Foundation/NSArchiver.h>
 #import "AppKit/NSSplitViewItem.h"
+#import "AppKit/NSViewController.h"
 
 @implementation NSSplitViewItem
 - (instancetype) initWithViewController: (NSViewController *)viewController

Source/NSViewController.m

@@ -37,6 +37,7 @@
 #import "AppKit/NSViewController.h"
 #import "AppKit/NSStoryboardSegue.h"
 #import "AppKit/NSStoryboard.h"
+#import "AppKit/NSWindow.h"
 #import "AppKit/NSWindowController.h"
 
 @implementation NSViewController