From https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=180565
--- a/interfaces/cc/aspell.h
+++ b/interfaces/cc/aspell.h
@@ -237,6 +237,7 @@
 /******************************** errors ********************************/
 
 
+#ifndef ASPELL_ERRORS__HPP
 extern const struct AspellErrorInfo * const aerror_other;
 extern const struct AspellErrorInfo * const aerror_operation_not_supported;
 extern const struct AspellErrorInfo * const   aerror_cant_copy;
@@ -322,6 +323,7 @@
 extern const struct AspellErrorInfo * const   aerror_bad_magic;
 extern const struct AspellErrorInfo * const aerror_expression;
 extern const struct AspellErrorInfo * const   aerror_invalid_expression;
+#endif
 
 
 /******************************* speller *******************************/
--- a/prog/aspell.cpp
+++ b/prog/aspell.cpp
@@ -25,6 +25,7 @@
 # include <langinfo.h>
 #endif
 
+#include "errors.hpp"
 #include "aspell.h"
 
 #ifdef USE_FILE_INO
@@ -40,7 +41,6 @@
 #include "convert.hpp"
 #include "document_checker.hpp"
 #include "enumeration.hpp"
-#include "errors.hpp"
 #include "file_util.hpp"
 #include "fstream.hpp"
 #include "info.hpp"
--- a/prog/checker_string.hpp
+++ b/prog/checker_string.hpp
@@ -6,6 +6,7 @@
 
 #include <stdio.h>
 
+#include "errors.hpp"
 #include "aspell.h"
 
 #include "vector.hpp"