unify include guard defines, __$FILENAME__

without the underscores these clogged up the namespace for autocompleation which was annoying.

source/blender/python/intern/bpy_driver.h

@@ -24,8 +24,8 @@
  *  \ingroup pythonintern
  */
 
-#ifndef BPY_DRIVER_H
-#define BPY_DRIVER_H
+#ifndef __BPY_DRIVER_H__
+#define __BPY_DRIVER_H__
 
 struct ChannelDriver;
 
@@ -36,4 +36,4 @@ extern PyObject *bpy_pydriver_Dict;
 float BPY_driver_exec(struct ChannelDriver *driver, const float evaltime);
 void BPY_driver_reset(void);
 
-#endif // BPY_DRIVER_H
+#endif // __BPY_DRIVER_H__