diff --git a/fluid/CMakeLists.txt b/fluid/CMakeLists.txt
index 647477d1a..e5cbdf0e3 100644
--- a/fluid/CMakeLists.txt
+++ b/fluid/CMakeLists.txt
@@ -22,8 +22,6 @@ set(CPPFILES
     Fl_Group_Type.cxx
     Fl_Menu_Type.cxx
     Fl_Type.cxx
-    ExternalCodeEditor_UNIX.cxx
-    ExternalCodeEditor_WIN32.cxx
     Fl_Widget_Type.cxx
     Fl_Window_Type.cxx
     Fluid_Image.cxx
@@ -40,6 +38,14 @@ set(CPPFILES
     widget_panel.cxx
 )
 
+# ExternalCodeEditor: platform specific files
+
+if (WIN32)
+    list(APPEND CPPFILES ExternalCodeEditor_WIN32.cxx)
+else ()
+    list(APPEND CPPFILES ExternalCodeEditor_UNIX.cxx)
+endif (WIN32)
+
 if(APPLE AND (NOT OPTION_APPLE_X11) AND (NOT OPTION_APPLE_SDL))
   set( ICON_NAME fluid.icns )
   set( ICON_PATH "${PROJECT_SOURCE_DIR}/fluid/Fluid.app/Contents/Resources/${ICON_NAME}" )
diff --git a/fluid/ExternalCodeEditor_UNIX.cxx b/fluid/ExternalCodeEditor_UNIX.cxx
index 06de7f503..ee6816b78 100644
--- a/fluid/ExternalCodeEditor_UNIX.cxx
+++ b/fluid/ExternalCodeEditor_UNIX.cxx
@@ -1,9 +1,9 @@
 //
 // "$Id$".
 //
-//       External code editor management class for Unix
+//	External code editor management class for Unix
 //
-#ifndef WIN32           /* This entire file unix only */
+//	Note: This entire file Unix only
 
 #include <errno.h>      /* errno */
 #include <string.h>     /* strerror() */
@@ -459,7 +459,6 @@ int ExternalCodeEditor::editors_open() {
   return L_editors_open;
 }
 
-#endif /* !WIN32 */
 //
 // End of "$Id$".
 //
diff --git a/fluid/ExternalCodeEditor_WIN32.cxx b/fluid/ExternalCodeEditor_WIN32.cxx
index ba7a2775c..105eaf702 100644
--- a/fluid/ExternalCodeEditor_WIN32.cxx
+++ b/fluid/ExternalCodeEditor_WIN32.cxx
@@ -1,10 +1,9 @@
 //
 // "$Id$".
 //
-//       External code editor management class for Windows
+//	External code editor management class for Windows
 //
-
-#ifdef WIN32	        /* This entire file windows only */
+//	Note: This entire file Windows only.
 
 #include <stdio.h>      // snprintf()
 
@@ -571,7 +570,6 @@ int ExternalCodeEditor::editors_open() {
   return L_editors_open;
 }
 
-#endif /* WIN32 */
 //
 // End of "$Id$".
 //
diff --git a/fluid/Makefile b/fluid/Makefile
index 4423c6934..1100c9a3b 100644
--- a/fluid/Makefile
+++ b/fluid/Makefile
@@ -3,7 +3,7 @@
 #
 # FLUID makefile for the Fast Light Tool Kit (FLTK).
 #
-# Copyright 1998-2016 by Bill Spitzak and others.
+# Copyright 1998-2017 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
@@ -16,10 +16,10 @@
 #      http://www.fltk.org/str.php
 #
 
+include ../makeinclude
+
 CPPFILES = \
 	CodeEditor.cxx \
-	ExternalCodeEditor_UNIX.cxx \
-	ExternalCodeEditor_WIN32.cxx \
 	Fl_Function_Type.cxx \
 	Fl_Group_Type.cxx \
 	Fl_Menu_Type.cxx \
@@ -39,12 +39,19 @@ CPPFILES = \
 	undo.cxx \
 	widget_panel.cxx
 
+# ExternalCodeEditor: platform specific files
+
+CPPFILES_WIN = ExternalCodeEditor_WIN32.cxx
+CPPFILES_OSX = ExternalCodeEditor_UNIX.cxx
+CPPFILES_X11 = ExternalCodeEditor_UNIX.cxx
+CPPFILES_XFT = ExternalCodeEditor_UNIX.cxx
+
+CPPFILES += $(CPPFILES_$(BUILD))
+
 ################################################################
 
 OBJECTS = $(CPPFILES:.cxx=.o)
 
-include ../makeinclude
-
 all:	$(FLUID) fluid$(EXEEXT)
 
 fluid$(EXEEXT):		$(OBJECTS) $(LIBNAME) $(FLLIBNAME) \
@@ -116,12 +123,12 @@ uninstall-osx:
 #
 
 rebuild:
-	./fluid -c about_panel.fl
-	./fluid -c alignment_panel.fl
-	./fluid -c function_panel.fl
-	./fluid -c print_panel.fl
-	./fluid -c template_panel.fl
-	./fluid -c widget_panel.fl
+	./fluid -u -c about_panel.fl
+	./fluid -u -c alignment_panel.fl
+	./fluid -u -c function_panel.fl
+	./fluid -u -c print_panel.fl
+	./fluid -u -c template_panel.fl
+	./fluid -u -c widget_panel.fl
 
 #
 # End of "$Id$".
diff --git a/makeinclude.in b/makeinclude.in
index 07a85d9b7..9f75653ee 100644
--- a/makeinclude.in
+++ b/makeinclude.in
@@ -26,7 +26,7 @@ FL_DSO_VERSION		= @FL_DSO_VERSION@
 FL_ABI_VERSION		= @FL_ABI_VERSION@
 FL_VERSION		= @FL_VERSION@
 
-# FLTK configuration options
+# FLTK configuration options: BUILD = { WIN | OSX | X11 | XFT }
 
 BUILD		= @BUILD@