Branch [/timeline?r=bug-4718b41c56|bug-4718b41c56] should fix this for x86 build >= 8.5 and CRT supporting 64-bit time_t and provides test-cases covering this bug.

Possibly it can (or should) be additionally protected by some define (or configure option/CFLAGS/etc) for binary compatibility across several windows platform if compiled and/or executed with different CRT-libraries.

Or we could simply rewrite it using something like this:
<code><pre>
<b style="color:green">+ #if defined(_USE_64BIT_TIME_T) || defined(TCL_FORCE_64BIT_TIME)</b>
...
<b style="color:green">+ #endif</b>
</pre></code>