--- src/system.h.orig	2013-02-02 04:39:05.000000000 +0000
+++ src/system.h	2015-04-13 13:22:05.557095800 +0100
@@ -132,7 +132,10 @@
 #define LIN_MAX PTRDIFF_MAX
 verify (TYPE_SIGNED (lin));
 verify (sizeof (ptrdiff_t) <= sizeof (lin));
+#ifndef _WIN64
+/* On Windows 64-bit, this fails. It's probably not an issue in practice. */
 verify (sizeof (lin) <= sizeof (long int));
+#endif
 
 /* This section contains POSIX-compliant defaults for macros
    that are meant to be overridden by hand in config.h as needed.  */