diff --git a/mercurial/bdiff.h b/mercurial/bdiff.h
--- a/mercurial/bdiff.h
+++ b/mercurial/bdiff.h
@@ -1,5 +1,5 @@
-#ifndef _HG_BDIFF_H_
-#define _HG_BDIFF_H_
+#ifndef HG_BDIFF_H
+#define HG_BDIFF_H
 
 #include "compat.h"
 
diff --git a/mercurial/bitmanipulation.h b/mercurial/bitmanipulation.h
--- a/mercurial/bitmanipulation.h
+++ b/mercurial/bitmanipulation.h
@@ -1,5 +1,5 @@
-#ifndef _HG_BITMANIPULATION_H_
-#define _HG_BITMANIPULATION_H_
+#ifndef HG_BITMANIPULATION_H
+#define HG_BITMANIPULATION_H
 
 #include <string.h>
 
diff --git a/mercurial/compat.h b/mercurial/compat.h
--- a/mercurial/compat.h
+++ b/mercurial/compat.h
@@ -1,5 +1,5 @@
-#ifndef _HG_COMPAT_H_
-#define _HG_COMPAT_H_
+#ifndef HG_COMPAT_H
+#define HG_COMPAT_H
 
 #ifdef _WIN32
 #ifdef _MSC_VER
diff --git a/mercurial/mpatch.h b/mercurial/mpatch.h
--- a/mercurial/mpatch.h
+++ b/mercurial/mpatch.h
@@ -1,5 +1,5 @@
-#ifndef _HG_MPATCH_H_
-#define _HG_MPATCH_H_
+#ifndef HG_MPATCH_H
+#define HG_MPATCH_H
 
 #define MPATCH_ERR_NO_MEM -3
 #define MPATCH_ERR_CANNOT_BE_DECODED -2