compat/winansi: check for errors of CreateThread() correctly

The return value for failed thread creation is NULL,
not INVALID_HANDLE_VALUE, unlike other Windows API functions.

Signed-off-by: Seija Kijin <doremylover123@gmail.com>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Seija Kijin

compat/winansi.c

@@ -644,7 +644,7 @@ void winansi_init(void)
 
 	/* start console spool thread on the pipe's read end */
 	hthread = CreateThread(NULL, 0, console_thread, NULL, 0, NULL);
-	if (hthread == INVALID_HANDLE_VALUE)
+	if (!hthread)
 		die_lasterr("CreateThread(console_thread) failed");
 
 	/* schedule cleanup routine */