Seems this file supports every archaic target in existence, but not MSVC. I've patched it like:
--- a/lib/fseeko.c 2016-01-30 20:42:16 +++ b/lib/fseeko.c 2016-01-31 10:25:06 @@ -100,7 +100,7 @@ #elif defined EPLAN9 /* Plan9 */ if (fp->rp == fp->buf && fp->wp == fp->buf) -#elif FUNC_FFLUSH_STDIN < 0 && 200809 <= _POSIX_VERSION +#elif FUNC_FFLUSH_STDIN < 0 && 200809 <= _POSIX_VERSION || _MSC_VER /* Cross-compiling to some other system advertising conformance to POSIX.1-2008 or later. Assume fseeko and fflush work as advertised. If this assumption is incorrect, please report the bug to but I've no idea if it's correct. Any pointers? -- --gv