diff --git a/windows/GNUfiles.mk b/windows/GNUfiles.mk
index b0387a52..a539d768 100644
--- a/windows/GNUfiles.mk
+++ b/windows/GNUfiles.mk
@@ -1,58 +1,58 @@
 # 22 april 2015
 
-CFILES += \
-	windows/alloc.c \
-	windows/area.c \
-	windows/areadraw.c \
-	windows/areaevents.c \
-	windows/areascroll.c \
-	windows/areautil.c \
-	windows/box.c \
-	windows/button.c \
-	windows/checkbox.c \
-	windows/child.c \
-	windows/combobox.c \
-	windows/container.c \
-	windows/control.c \
-	windows/d2dscratch.c \
-	windows/datetimepicker.c \
-	windows/debug.c \
-	windows/draw.c \
-	windows/entry.c \
-	windows/events.c \
-	windows/group.c \
-	windows/init.c \
-	windows/label.c \
-	windows/main.c \
-	windows/menu.c \
-	windows/multilineentry.c \
-	windows/parent.c \
-	windows/progressbar.c \
-	windows/radiobuttons.c \
-	windows/resize.c \
-	windows/separator.c \
-	windows/slider.c \
-	windows/spinbox.c \
-	windows/stddialogs.c \
-	windows/tab.c \
-	windows/tabpage.c \
-	windows/text.c \
-	windows/util.c \
-	windows/utilwin.c \
-	windows/window.c
-
 CXXFILES += \
+	windows/alloc.cpp \
+	windows/area.cpp \
+	windows/areadraw.cpp \
+	windows/areaevents.cpp \
+	windows/areascroll.cpp \
+	windows/areautil.cpp \
+	windows/box.cpp \
+	windows/button.cpp \
+	windows/checkbox.cpp \
+	windows/child.cpp \
+	windows/combobox.cpp \
+	windows/container.cpp \
+	windows/control.cpp \
+	windows/d2dscratch.cpp \
+	windows/datetimepicker.cpp \
+	windows/debug.cpp \
+	windows/draw.cpp \
 	windows/drawtext.cpp \
 	windows/dwrite.cpp \
+	windows/entry.cpp \
+	windows/events.cpp \
 	windows/fontbutton.cpp \
-	windows/fontdialog.cpp
+	windows/fontdialog.cpp \
+	windows/group.cpp \
+	windows/init.cpp \
+	windows/label.cpp \
+	windows/main.cpp \
+	windows/menu.cpp \
+	windows/multilineentry.cpp \
+	windows/parent.cpp \
+	windows/progressbar.cpp \
+	windows/radiobuttons.cpp \
+	windows/resize.cpp \
+	windows/separator.cpp \
+	windows/slider.cpp \
+	windows/spinbox.cpp \
+	windows/stddialogs.cpp \
+	windows/tab.cpp \
+	windows/tabpage.cpp \
+	windows/text.cpp \
+	windows/utf16.cpp \
+	windows/utilwin.cpp \
+	windows/window.cpp \
+	windows/winutil.cpp
 
 HFILES += \
-	windows/area.h \
-	windows/compilerver.h \
-	windows/resources.h \
-	windows/uipriv_windows.h \
-	windows/winapi.h
+	windows/_uipriv_migrate.hpp \
+	windows/area.hpp \
+	windows/compilerver.hpp \
+	windows/resources.hpp \
+	windows/uipriv_windows.hpp \
+	windows/winapi.hpp
 
 RCFILES += \
 	windows/resources.rc