diff --git a/src/Xutf8.h b/src/Xutf8.h
index 8fe0ba0cb..050226500 100644
--- a/src/Xutf8.h
+++ b/src/Xutf8.h
@@ -156,24 +156,6 @@ XUtf8LookupString(
     Status*             status_return);
 #endif
 
-unsigned short
-XUtf8IsNonSpacing(
-	unsigned int ucs);
-
-unsigned short
-XUtf8IsRightToLeft(
-        unsigned int ucs);
-
-
-int
-XUtf8Tolower(
-        int ucs);
-
-int
-XUtf8Toupper(
-        int ucs);
-
-
 #  ifdef __cplusplus
 }
 #  endif
diff --git a/src/fl_utf8.cxx b/src/fl_utf8.cxx
index 7ae9f1f8f..b7d58eecd 100644
--- a/src/fl_utf8.cxx
+++ b/src/fl_utf8.cxx
@@ -23,15 +23,12 @@
 #include <FL/filename.H>
 #include <stdarg.h>
 #include <FL/fl_utf8.h>
+#include "utf8_internal.h"
+
 #include <string.h>
 #include <stdlib.h>
 
 #undef fl_open
-extern "C" {
-  int XUtf8Tolower(int ucs); // in src/xutf8/case.c
-  unsigned short XUtf8IsNonSpacing(unsigned int ucs); // in src/xutf8/is_spacing.c
-}
-
 
 /** \addtogroup fl_unicode
     @{
diff --git a/src/utf8_internal.h b/src/utf8_internal.h
new file mode 100644
index 000000000..6d5def687
--- /dev/null
+++ b/src/utf8_internal.h
@@ -0,0 +1,62 @@
+/*
+ * "$Id$"
+ *
+ * Internal UTF-8 header file for the Fast Light Tool Kit (FLTK).
+ *
+ * Copyright 1998-2016 by Bill Spitzak and others.
+ *
+ * This library is free software. Distribution and use rights are outlined in
+ * the file "COPYING" which should have been included with this file.  If this
+ * file is missing or damaged, see the license at:
+ *
+ *     http://www.fltk.org/COPYING.php
+ *
+ * Please report all bugs and problems on the following page:
+ *
+ *     http://www.fltk.org/str.php
+ */
+
+/*
+  ----------------
+  Note to editors:
+  ----------------
+
+  This file may only contain common, platform-independent function
+  declarations used internally in FLTK. It may be #included everywhere
+  in source files in the library, but not in public header files.
+*/
+
+#ifndef _SRC__FL_UTF8_H
+#define _SRC__FL_UTF8_H
+
+#  ifdef __cplusplus
+extern "C" {
+#  endif
+
+unsigned short
+XUtf8IsNonSpacing(
+	unsigned int ucs);
+
+unsigned short
+XUtf8IsRightToLeft(
+        unsigned int ucs);
+
+
+int
+XUtf8Tolower(
+        int ucs);
+
+int
+XUtf8Toupper(
+        int ucs);
+
+
+#  ifdef __cplusplus
+}
+#  endif
+
+#endif /* _SRC__FL_UTF8_H */
+
+/*
+ *  End of "$Id$".
+ */
diff --git a/src/xutf8/case.c b/src/xutf8/case.c
index de97348cf..e6589cc5b 100644
--- a/src/xutf8/case.c
+++ b/src/xutf8/case.c
@@ -19,7 +19,7 @@
  * This file is required on all platforms for UTF-8 support
  */
 
-#include "../Xutf8.h"
+#include "../utf8_internal.h"
 #include <stdlib.h>
 
 /* include UCS tables */
diff --git a/src/xutf8/is_right2left.c b/src/xutf8/is_right2left.c
index e79a55f25..c36a0829b 100644
--- a/src/xutf8/is_right2left.c
+++ b/src/xutf8/is_right2left.c
@@ -14,22 +14,11 @@
  *     http://www.fltk.org/str.php
  */
 
-#if defined(WIN32) || defined(__APPLE__) /* PORTME: Fl_Screen_Driver - platform unicode */
-#elif defined(FL_PORTING)
-#  pragma message "FL_PORTING: utf8 functionality"
-#else
-#endif
-
 /*
- * This file is required on all platforms for utf8 support
+ * This file is required on all platforms for UTF-8 support
  */
 
-#if defined(WIN32) || defined(__APPLE__)
-#elif defined(FL_PORTING)
-#  pragma message "FL_PORTING: do you want to include Xutf8.h? It's written for X11."
-#else
-#  include "../Xutf8.h"
-#endif /* !defined(WIN32) && !defined(__APPLE__) */
+#include "../utf8_internal.h"
 
 unsigned short
 XUtf8IsRightToLeft(unsigned int ucs) {
diff --git a/src/xutf8/is_spacing.c b/src/xutf8/is_spacing.c
index 30229e72e..72e4df4e8 100644
--- a/src/xutf8/is_spacing.c
+++ b/src/xutf8/is_spacing.c
@@ -18,7 +18,7 @@
  * This file is required on all platforms for UTF-8 support
  */
 
-#include "../Xutf8.h"
+#include "../utf8_internal.h"
 
 /* include UCS tables */
 #include "headers/spacing.h"