Ninja: Add a missed license header

Source/cmNinjaUtilityTargetGenerator.cxx

@@ -1,3 +1,15 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2011 Peter Collingbourne <[email protected]>
+  Copyright 2011 Nicolas Despres <[email protected]>
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
 #include "cmNinjaUtilityTargetGenerator.h"
 #include "cmCustomCommand.h"
 #include "cmGeneratedFileStream.h"