Fixup kiway by hand when dynamic_cast fails.

Also allows a shortened version of Configure Paths without the 3D
paths when Pcbnew isn't already running.

Fixes https://gitlab.com/kicad/code/kicad/issues/4568

common/tool/common_control.cpp

@@ -77,16 +77,31 @@ void COMMON_CONTROL::Reset( RESET_REASON aReason )
 
 int COMMON_CONTROL::ConfigurePaths( const TOOL_EVENT& aEvent )
 {
-    try     // _pcbnew.kiface must be available: it contains the configure path dialog.
+    // If _pcbnew.kiface is running have it put up the dialog so the 3D paths can also
+    // be edited
+    KIFACE* pcbnew = m_frame->Kiway().KiFACE( KIWAY::FACE_PCB, false );
+
+    if( pcbnew )
     {
-        KIFACE* kiface = m_frame->Kiway().KiFACE( KIWAY::FACE_PCB );
-        kiface->CreateWindow( m_frame, DIALOG_CONFIGUREPATHS, &m_frame->Kiway() );
+        try
+        {
+            pcbnew->CreateWindow( m_frame, DIALOG_CONFIGUREPATHS, &m_frame->Kiway() );
+        }
+        catch( ... )
+        {
+            // Do nothing here.
+            // A error message is displayed after trying to load _pcbnew.kiface.
+        }
     }
-    catch( ... )
+    else
     {
-        // Do nothing here.
-        // A error message is displayed after trying to load _pcbnew.kiface.
+        DIALOG_CONFIGURE_PATHS dlg( m_frame, nullptr );
+
+        if( dlg.ShowModal() == wxID_OK )
+            m_frame->Kiway().CommonSettingsChanged( true );
     }
+
+
     return 0;
 }
 

pcbnew/pcbnew.cpp

@@ -114,6 +114,11 @@ static struct IFACE : public KIFACE_I
         {
             DIALOG_CONFIGURE_PATHS dlg( aParent, aKiway->Prj().Get3DFilenameResolver() );
 
+            // The dialog's constructor probably failed to set its Kiway because the
+            // dynamic_cast fails when aParent was allocated by a separate compiliation
+            // module.  So set it directly.
+            dlg.SetKiway( &dlg, aKiway );
+
             if( dlg.ShowModal() == wxID_OK )
                 aKiway->CommonSettingsChanged( true );