FP editor: fix crash when trying to save a footprint (Ctrl+S) when no footprint loaded.

pcbnew/footprint_editor_utils.cpp

@@ -255,6 +255,9 @@ void FOOTPRINT_EDIT_FRAME::Process_Special_Functions( wxCommandEvent& event )
         break;
 
     case ID_MODEDIT_SAVE:
+        if( !GetBoard()->GetFirstModule() )     // no loaded footprint
+            break;
+
         if( GetTargetFPID() == GetLoadedFPID() )
         {
             if( SaveFootprint( GetBoard()->GetFirstModule() ) )

pcbnew/footprint_libraries_utils.cpp

@@ -706,6 +706,9 @@ void PCB_EDIT_FRAME::ArchiveModulesOnBoard( bool aStoreInNewLib, const wxString&
 
 bool FOOTPRINT_EDIT_FRAME::SaveFootprint( MODULE* aModule )
 {
+    if( !aModule )      // Happen if no footprint loaded
+        return false;
+
     wxString libraryName = aModule->GetFPID().GetLibNickname();
     wxString footprintName = aModule->GetFPID().GetLibItemName();
     bool nameChanged = m_footprintNameWhenLoaded != footprintName;