From Markus Trenkwalder, "Mingws gcc includes a file called types.h which in turn defines

_TYPES_H_.  types.h in the directx plugin defines the same include
guard.  I've renamed the guard name in this file to _DX_TYPES_H_.  Now
the plugin compile in mingw too."

src/osgPlugins/directx/types.h

@@ -21,8 +21,8 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#ifndef _TYPES_H_
-#define _TYPES_H_
+#ifndef _DX_TYPES_H_
+#define _DX_TYPES_H_
 
 #include <string>
 #include <vector>