PAGED_DIALOG: fix an issue related to TransferDataFromWindow and TransferDataToWindow, on wxWidgets 3.0

On wxWidgets 3.1 they are called recursively but not on on wxWidgets 3.0.
We call now TransferDataToWindow and TransferDataFromWindow only once,
but ensure it is called for all pages.

Fixes: lp:1836901
https://bugs.launchpad.net/kicad/+bug/1836901

common/widgets/paged_dialog.cpp

@@ -1,7 +1,7 @@
 /*
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
- * Copyright (C) 2018 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2019 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software: you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -141,10 +141,14 @@ bool PAGED_DIALOG::TransferDataToWindow()
 {
     finishInitialization();
 
-    #if 1   // Call TransferDataToWindow() only once: this is enough
+    // Call TransferDataToWindow() only once:
+    // this is enough on wxWidgets 3.1
     if( !DIALOG_SHIM::TransferDataToWindow() )
         return false;
-    #else
+
+    // On wxWidgets 3.0, TransferDataFromWindow() is not called recursively
+    // so we have to call it for each page
+#if !wxCHECK_VERSION( 3, 1, 0 )
     for( size_t i = 0; i < m_treebook->GetPageCount(); ++i )
     {
         wxWindow* page = m_treebook->GetPage( i );
@@ -152,7 +156,7 @@ bool PAGED_DIALOG::TransferDataToWindow()
         if( !page->TransferDataToWindow() )
             return false;
     }
-    #endif
+#endif
 
     // Search for a page matching the lastParentPageTitle/lastPageTitle hierarchy
     wxString lastPage = g_lastPage[ m_title ];
@@ -186,10 +190,14 @@ bool PAGED_DIALOG::TransferDataToWindow()
 
 bool PAGED_DIALOG::TransferDataFromWindow()
 {
-    #if 1   // Call TransferDataFromWindow() only once: this is enough
+    // Call TransferDataFromWindow() only once:
+    // this is enough on wxWidgets 3.1
     if( !DIALOG_SHIM::TransferDataFromWindow() )
         return false;
-    #else
+
+    // On wxWidgets 3.0, TransferDataFromWindow() is not called recursively
+    // so we have to call it for each page
+#if !wxCHECK_VERSION( 3, 1, 0 )
     for( size_t i = 0; i < m_treebook->GetPageCount(); ++i )
     {
         wxWindow* page = m_treebook->GetPage( i );
@@ -197,7 +205,7 @@ bool PAGED_DIALOG::TransferDataFromWindow()
         if( !page->TransferDataFromWindow() )
             return false;
     }
-    #endif
+#endif
 
     return true;
 }