normalize header guards to {tu_name}_H_ (#87)

i previously had a bad habit of using double underscores in include
guard macro names, which are implementation-reserved per
the C++98 standard (see 17.4.3.1.2 Global names).

Co-authored-by: Pheenoh <pheenoh@gmail.com>

include/Z2AudioLib/Z2AudioMgr/Z2AudioMgr.h

@@ -1,5 +1,5 @@
-#ifndef __Z2AUDIOMGR_H__
-#define __Z2AUDIOMGR_H__
+#ifndef Z2AUDIOMGR_H_
+#define Z2AUDIOMGR_H_
 
 extern "C" {
 void Z2AudioMgr_NS_setOutputMode(void*, unsigned long);

include/Z2AudioLib/Z2EnvSeMgr/Z2EnvSeMgr.h

@@ -1,5 +1,5 @@
-#ifndef __Z2ENVSEMGR_H__
-#define __Z2ENVSEMGR_H__
+#ifndef Z2ENVSEMGR_H_
+#define Z2ENVSEMGR_H_
 
 extern void* lbl_80450B3C;  // Z2EnvSeMgr sInstance
 

include/Z2AudioLib/Z2Param/Z2Param.h

@@ -1,5 +1,5 @@
-#ifndef __Z2PARAM_H__
-#define __Z2PARAM_H__
+#ifndef Z2PARAM_H_
+#define Z2PARAM_H_
 
 #include "dolphin/types.h"
 

include/Z2AudioLib/Z2SoundMgr/Z2SoundMgr.h

@@ -1,5 +1,5 @@
-#ifndef __Z2SOUNDMGR_H__
-#define __Z2SOUNDMGR_H__
+#ifndef Z2SOUNDMGR_H_
+#define Z2SOUNDMGR_H_
 
 class Z2SoundMgr;