diff --git a/nufxlib/MiscStuff.h b/nufxlib/MiscStuff.h
index 7af87ee..493985c 100644
--- a/nufxlib/MiscStuff.h
+++ b/nufxlib/MiscStuff.h
@@ -6,8 +6,8 @@
  * Misc stuff (shared between nufxlib and nulib2).  This is a collection
  * of miscellaneous types and macros that I find generally useful.
  */
-#ifndef __MiscStuff__
-#define __MiscStuff__
+#ifndef NUFXLIB_MISCSTUFF_H
+#define NUFXLIB_MISCSTUFF_H
 
 #define VALGRIND        /* assume we're using it */
 
@@ -102,4 +102,4 @@ typedef unsigned char Boolean;
 
 #define kInvalidPtr     ((void*)0xa3a3a3a3)
 
-#endif /*__MiscStuff__*/
+#endif /*NUFXLIB_MISCSTUFF_H*/
diff --git a/nufxlib/NufxLib.h b/nufxlib/NufxLib.h
index ca0487b..958f877 100644
--- a/nufxlib/NufxLib.h
+++ b/nufxlib/NufxLib.h
@@ -6,8 +6,8 @@
  *
  * External interface (types, defines, and function prototypes).
  */
-#ifndef __NufxLib__
-#define __NufxLib__
+#ifndef NUFXLIB_NUFXLIB_H
+#define NUFXLIB_NUFXLIB_H
 
 #include <stdio.h>
 #include <stdint.h>
@@ -841,4 +841,4 @@ NUFXLIB_API NuCallback NuSetGlobalErrorMessageHandler(NuCallback messageHandlerF
 }
 #endif
 
-#endif /*__NufxLib__*/
+#endif /*NUFXLIB_NUFXLIB_H*/
diff --git a/nufxlib/NufxLibPriv.h b/nufxlib/NufxLibPriv.h
index 012e9d7..3c2d714 100644
--- a/nufxlib/NufxLibPriv.h
+++ b/nufxlib/NufxLibPriv.h
@@ -6,8 +6,8 @@
  *
  * Global internal declarations and definitions.
  */
-#ifndef __NufxLibPriv__
-#define __NufxLibPriv__
+#ifndef NUFXLIB_NUFXLIBPRIV_H
+#define NUFXLIB_NUFXLIBPRIV_H
 
 /* include files that everybody needs */
 #include "SysDefs.h"
@@ -870,4 +870,4 @@ NuThreadFormat Nu_ConvertCompressValToFormat(NuArchive* pArchive,
 NuError Nu_GetVersion(long* pMajorVersion, long* pMinorVersion,
     long* pBugVersion, const char** ppBuildDate, const char** ppBuildFlags);
 
-#endif /*__NufxLibPriv__*/
+#endif /*NUFXLIB_NUFXLIBPRIV_H*/
diff --git a/nufxlib/SunOS4.h b/nufxlib/SunOS4.h
index 8db6562..ea2193b 100644
--- a/nufxlib/SunOS4.h
+++ b/nufxlib/SunOS4.h
@@ -8,8 +8,8 @@
  * (such as gcc) is used.  The system header files aren't quite sufficient
  * to eliminate hordes of warnings.
  */
-#ifndef __SunOS4__
-#define __SunOS4__
+#ifndef NUFXLIB_SUNOS4_H
+#define NUFXLIB_SUNOS4_H
 
 #ifdef __GNUC__
 extern int      _flsbuf(int, FILE*);
@@ -43,4 +43,4 @@ extern int      toupper(int);
 extern int      vfprintf(FILE*, const char *, va_list);
 extern char*    vsprintf(char *str, const char *format, va_list ap);
 
-#endif /*__SunOS4__*/
+#endif /*NUFXLIB_SUNOS4_H*/
diff --git a/nufxlib/SysDefs.h b/nufxlib/SysDefs.h
index 71b102e..290f759 100644
--- a/nufxlib/SysDefs.h
+++ b/nufxlib/SysDefs.h
@@ -6,8 +6,8 @@
  *
  * External type definitions and function prototypes.
  */
-#ifndef __SysDefs__
-#define __SysDefs__
+#ifndef NUFXLIB_SYSDEFS_H
+#define NUFXLIB_SYSDEFS_H
 
 #ifdef HAVE_CONFIG_H
 # include <config.h>
@@ -140,4 +140,4 @@
 # define HAS_MALLOC_CHECK_
 #endif
 
-#endif /*__SysDefs__*/
+#endif /*NUFXLIB_SYSDEFS_H*/
diff --git a/nulib2/MiscStuff.h b/nulib2/MiscStuff.h
index 7af87ee..494d61a 100644
--- a/nulib2/MiscStuff.h
+++ b/nulib2/MiscStuff.h
@@ -6,8 +6,8 @@
  * Misc stuff (shared between nufxlib and nulib2).  This is a collection
  * of miscellaneous types and macros that I find generally useful.
  */
-#ifndef __MiscStuff__
-#define __MiscStuff__
+#ifndef NULIB2_MISCSTUFF_H
+#define NULIB2_MISCSTUFF_H
 
 #define VALGRIND        /* assume we're using it */
 
@@ -102,4 +102,4 @@ typedef unsigned char Boolean;
 
 #define kInvalidPtr     ((void*)0xa3a3a3a3)
 
-#endif /*__MiscStuff__*/
+#endif /*NULIB2_MISCSTUFF_H*/
diff --git a/nulib2/Nulib2.h b/nulib2/Nulib2.h
index 7f192bf..2323f65 100644
--- a/nulib2/Nulib2.h
+++ b/nulib2/Nulib2.h
@@ -4,8 +4,8 @@
  * This is free software; you can redistribute it and/or modify it under the
  * terms of the BSD License, see the file COPYING.
  */
-#ifndef __Nulib2__
-#define __Nulib2__
+#ifndef NULIB2_NULIB2_H
+#define NULIB2_NULIB2_H
 
 #include "SysDefs.h"    /* system-dependent defs; must come first */
 #include <NufxLib.h>
@@ -110,4 +110,4 @@ NuError AddFile(NulibState* pState, NuArchive* pArchive,
 NuError Mkdir(const char* dir);
 NuError TestFileExistence(const char* fileName, Boolean* pIsDir);
 
-#endif /*__Nulib2__*/
+#endif /*NULIB2_NULIB2_H*/
diff --git a/nulib2/State.h b/nulib2/State.h
index ad05a6d..0ae31ae 100644
--- a/nulib2/State.h
+++ b/nulib2/State.h
@@ -4,8 +4,8 @@
  * This is free software; you can redistribute it and/or modify it under the
  * terms of the BSD License, see the file COPYING.
  */
-#ifndef __State__
-#define __State__
+#ifndef NULIB2_STATE_H
+#define NULIB2_STATE_H
 
 #include "MiscStuff.h"
 #include "NufxLib.h"
@@ -154,4 +154,4 @@ void NState_SetModPreserveType(NulibState* pState, Boolean val);
 Boolean NState_GetModPreserveTypeExtended(const NulibState* pState);
 void NState_SetModPreserveTypeExtended(NulibState* pState, Boolean val);
 
-#endif /*__State__*/
+#endif /*NULIB2_STATE_H*/
diff --git a/nulib2/SunOS4.h b/nulib2/SunOS4.h
index 8db6562..ccf2ba9 100644
--- a/nulib2/SunOS4.h
+++ b/nulib2/SunOS4.h
@@ -8,8 +8,8 @@
  * (such as gcc) is used.  The system header files aren't quite sufficient
  * to eliminate hordes of warnings.
  */
-#ifndef __SunOS4__
-#define __SunOS4__
+#ifndef NULIB2_SUNOS4_H
+#define NULIB2_SUNOS4_H
 
 #ifdef __GNUC__
 extern int      _flsbuf(int, FILE*);
@@ -43,4 +43,4 @@ extern int      toupper(int);
 extern int      vfprintf(FILE*, const char *, va_list);
 extern char*    vsprintf(char *str, const char *format, va_list ap);
 
-#endif /*__SunOS4__*/
+#endif /*NULIB2_SUNOS4_H*/
diff --git a/nulib2/SysDefs.h b/nulib2/SysDefs.h
index f04a041..b7b7844 100644
--- a/nulib2/SysDefs.h
+++ b/nulib2/SysDefs.h
@@ -6,8 +6,8 @@
  *
  * This was adapted from gzip's "tailor.h" and NuLib's "nudefs.h".
  */
-#ifndef __SysDefs__
-#define __SysDefs__
+#ifndef NULIB2_SYSDEFS_H
+#define NULIB2_SYSDEFS_H
 
 #ifdef HAVE_CONFIG_H
 # include <config.h>
@@ -208,4 +208,4 @@
 # define MAX_PATH_LEN   1024
 #endif
 
-#endif /*__SysDefs__*/
+#endif /*NULIB2_SYSDEFS_H*/