diff --git a/source.list b/source.list
index 26a7a0aa24..0fa314996c 100644
--- a/source.list
+++ b/source.list
@@ -344,6 +344,7 @@ story_type.h
 strgen/strgen.h
 string_base.h
 string_func.h
+string_func_extra.h
 string_type.h
 stringfilter_type.h
 strings_func.h
diff --git a/src/saveload/saveload.cpp b/src/saveload/saveload.cpp
index a94bbf785f..a6472f4fc3 100644
--- a/src/saveload/saveload.cpp
+++ b/src/saveload/saveload.cpp
@@ -41,6 +41,7 @@
 #include "../fileio_func.h"
 #include "../gamelog.h"
 #include "../string_func.h"
+#include "../string_func_extra.h"
 #include "../fios.h"
 #include "../error.h"
 
diff --git a/src/string_func.h b/src/string_func.h
index 70214ff8d1..f5dd289499 100644
--- a/src/string_func.h
+++ b/src/string_func.h
@@ -27,7 +27,6 @@
 #define STRING_FUNC_H
 
 #include <stdarg.h>
-#include <string>
 
 #include "core/bitmath_func.hpp"
 #include "string_type.h"
@@ -56,13 +55,6 @@ static inline void str_validate(char *str, const char *last, StringValidationSet
 	*str_validate_intl(str, last, settings) = '\0';
 }
 
-static inline void str_validate(std::string &str, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK)
-{
-	if (str.empty()) return;
-	char *buf = const_cast<char *>(str.c_str());
-	str.resize(str_validate_intl(buf, buf + str.size(), settings) - buf);
-}
-
 void ValidateString(const char *str);
 
 void str_fix_scc_encoded(char *str, const char *last);
diff --git a/src/string_func_extra.h b/src/string_func_extra.h
new file mode 100644
index 0000000000..9c320f3ea2
--- /dev/null
+++ b/src/string_func_extra.h
@@ -0,0 +1,23 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef STRING_FUNC_EXTRA_H
+#define STRING_FUNC_EXTRA_H
+
+#include "string_func.h"
+#include <string>
+
+static inline void str_validate(std::string &str, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK)
+{
+	if (str.empty()) return;
+	char *buf = const_cast<char *>(str.c_str());
+	str.resize(str_validate_intl(buf, buf + str.size(), settings) - buf);
+}
+
+#endif /* STRING_FUNC_EXTRA_H */