Include tkinter.h only after including tk.h (or the equivalent for another platform).
diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 775598c..ea36297 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -33,8 +33,6 @@
#include <windows.h>
#endif
-#include "tkinter.h"
-
/* Allow using this code in Python 2.[12] */
#ifndef PyDoc_STRVAR
#define PyDoc_STRVAR(name,str) static char name[] = str
@@ -69,6 +67,8 @@
#include <tk.h>
#endif
+#include "tkinter.h"
+
/* For Tcl 8.2 and 8.3, CONST* is not defined (except on Cygwin). */
#ifndef CONST84_RETURN
#define CONST84_RETURN
diff --git a/Modules/tkinter.h b/Modules/tkinter.h
index 57be878..f7e50cd 100644
--- a/Modules/tkinter.h
+++ b/Modules/tkinter.h
@@ -2,7 +2,9 @@
#define TKINTER_H
/* This header is used to share some macros between _tkinter.c and
- * tkappinit.c */
+ * tkappinit.c.
+ * Be sure to include tk.h before including this header so
+ * TK_VERSION_HEX is properly defined. */
/* TK_RELEASE_LEVEL is always one of the following:
* TCL_ALPHA_RELEASE 0