From Alberto Luaces, "here are two minimal capitalization fixes for mingw cross-compilation, where case sensitivity matters."

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@15169 16af8721-9629-0410-8352-f15c8da7e697

src/osg/DisplaySettings.cpp

@@ -24,7 +24,7 @@ using namespace osg;
 using namespace std;
 
 #if defined(WIN32) && !defined(__CYGWIN__)
-#include<Windows.h>
+#include<windows.h>
 extern "C" { OSG_EXPORT DWORD NvOptimusEnablement=0x00000001; }
 #else
 extern "C" { int NvOptimusEnablement=0x00000001; }