Improve #include guard macros

Avoid using reserved identifiers such as `_DOHINT_H` (fixes #1989),
fix cases where the name doesn't match the filename, and make the naming
more consistent and less likely to collide with include guards in other
headers.

Source/Doxygen/doxyentity.h

@@ -11,8 +11,8 @@
  * Part of the Doxygen comment translation module of SWIG.
  * ----------------------------------------------------------------------------- */
 
-#ifndef DOXYGENENTITY_H_
-#define DOXYGENENTITY_H_
+#ifndef SWIG_DOXYENTITY_H
+#define SWIG_DOXYENTITY_H
 
 #include <string>
 #include <list>

Source/Doxygen/doxyparser.h

@@ -9,8 +9,8 @@
  * doxyparser.h
  * ----------------------------------------------------------------------------- */
 
-#ifndef DOXYGENPARSER_H_
-#define DOXYGENPARSER_H_
+#ifndef SWIG_DOXYPARSER_H
+#define SWIG_DOXYPARSER_H
 #include <string>
 #include <list>
 #include <map>

Source/Doxygen/doxytranslator.h

@@ -12,8 +12,8 @@
  * systems.
  * ----------------------------------------------------------------------------- */
 
-#ifndef DOXYGENTRANSLATOR_H_
-#define DOXYGENTRANSLATOR_H_
+#ifndef SWIG_DOXYTRANSLATOR_H
+#define SWIG_DOXYTRANSLATOR_H
 
 #include "swig.h"
 #include "doxyentity.h"

Source/Doxygen/javadoc.h

@@ -11,8 +11,8 @@
  * Module to return documentation for nodes formatted for JavaDoc
  * ----------------------------------------------------------------------------- */
 
-#ifndef JAVADOCCONVERTER_H_
-#define JAVADOCCONVERTER_H_
+#ifndef SWIG_JAVADOC_H
+#define SWIG_JAVADOC_H
 
 #include "doxytranslator.h"
 #include <map>

Source/Doxygen/pydoc.h

@@ -11,8 +11,8 @@
  * Module to return documentation for nodes formatted for PyDoc
  * ----------------------------------------------------------------------------- */
 
-#ifndef PYDOCCONVERTER_H_
-#define PYDOCCONVERTER_H_
+#ifndef SWIG_PYDOC_H
+#define SWIG_PYDOC_H
 
 #include <list>
 #include <string>