Issue #16840. Turn off bignum support in tkinter with with Tcl earlier than 8.5.8

(tclTomMath.h was broken) and non-final Tcl 8.6.

Modules/_tkinter.c

@@ -80,7 +80,7 @@ Copyright (C) 1994 Steen Lumholt.
 #define CONST
 #endif
 
-#if TK_VERSION_HEX < 0x08030102
+#if TK_HEX_VERSION < 0x08030201
 #error "Tk older than 8.3.1 not supported"
 #endif
 
@@ -96,7 +96,8 @@ Copyright (C) 1994 Steen Lumholt.
 #error "unsupported Tcl configuration"
 #endif
 
-#if TK_VERSION_HEX >= 0x08050002
+#if TK_HEX_VERSION >= 0x08050208 && TK_HEX_VERSION < 0x08060000 || \
+    TK_HEX_VERSION >= 0x08060200
 #define HAVE_LIBTOMMAMTH
 #include <tclTomMath.h>
 #endif
@@ -1405,7 +1406,7 @@ FromObj(PyObject* tkapp, Tcl_Obj *value)
 #endif
     }
 
-#if TK_VERSION_HEX >= 0x08050000
+#if TK_HEX_VERSION >= 0x08050000
     if (app->BooleanType == NULL &&
         strcmp(value->typePtr->name, "booleanString") == 0) {
         /* booleanString type is not registered in Tcl */

Modules/tkinter.h

@@ -4,24 +4,32 @@
 /* This header is used to share some macros between _tkinter.c and
  * tkappinit.c.
  * Be sure to include tk.h before including this header so
- * TK_VERSION_HEX is properly defined. */
+ * TK_HEX_VERSION is properly defined. */
 
 /* TK_RELEASE_LEVEL is always one of the following:
- *	TCL_ALPHA_RELEASE   0
+ *  TCL_ALPHA_RELEASE   0
  *  TCL_BETA_RELEASE    1
  *  TCL_FINAL_RELEASE   2
  */
+#define TK_HEX_VERSION ((TK_MAJOR_VERSION << 24) | \
+                        (TK_MINOR_VERSION << 16) | \
+                        (TK_RELEASE_LEVEL << 8) | \
+                        (TK_RELEASE_SERIAL << 0))
+
+/* TK_VERSION_HEX packs fields in wrong order, not suitable for comparing of
+ * non-final releases.  Left for backward compatibility.
+ */
 #define TK_VERSION_HEX ((TK_MAJOR_VERSION << 24) | \
-		(TK_MINOR_VERSION << 16) | \
-		(TK_RELEASE_SERIAL << 8) | \
-		(TK_RELEASE_LEVEL << 0))
+                        (TK_MINOR_VERSION << 16) | \
+                        (TK_RELEASE_SERIAL << 8) | \
+                        (TK_RELEASE_LEVEL << 0))
 
 /* Protect Tk 8.4.13 and older from a deadlock that happens when trying
  * to load tk after a failed attempt. */
-#if TK_VERSION_HEX < 0x08040e02
+#if TK_HEX_VERSION < 0x0804020e
 #define TKINTER_PROTECT_LOADTK
 #define TKINTER_LOADTK_ERRMSG \
-	"Calling Tk_Init again after a previous call failed might deadlock"
+        "Calling Tk_Init again after a previous call failed might deadlock"
 #endif
 
 #endif /* !TKINTER_H */