Add header guards to InterfaceBase.h

Source/Core/DolphinWX/Src/VideoInterface/InterfaceBase.h

@@ -14,7 +14,8 @@
 
 // Official SVN repository and contact information can be found at
 // http://code.google.com/p/dolphin-emu/
-
+#ifndef _GLINTERFACEBASE_H_
+#define _GLINTERFACEBASE_H_
 class cInterfaceBase
 {
 protected:
@@ -33,4 +34,4 @@ public:
 	virtual void Update() { } 
 	virtual bool PeekMessages() { return false; }
 };
-
+#endif