zig std regression

[andrewrk]

Even after build failures are fixed in #24743:

andy@bark ~/s/z/build-release (BufferedWriter)> ZIG_DEBUG_CMD=1 stage3/bin/zig std
http://127.0.0.1:39491/
thread 2599961 panic: integer overflow
/home/andy/src/zig/lib/std/http.zig:1026:51: 0x11beb73 in chunkedSendFile (std.zig)
                    chunked.chunk_len = chunk_len - n;
                                                  ^
/home/andy/src/zig/lib/std/Io/Writer.zig:895:29: 0x1207d0b in sendFile (std.zig)
    return w.vtable.sendFile(w, file_reader, limit);
                            ^
/home/andy/src/zig/lib/std/Io/Writer.zig:930:27: 0x11c3b27 in sendFileAll (std.zig)
        const n = sendFile(w, file_reader, .limited(remaining)) catch |err| switch (err) {
                          ^
/home/andy/src/zig/lib/std/tar/Writer.zig:57:44: 0x119b0eb in writeFile (std.zig)
    _ = try w.underlying_writer.sendFileAll(file_reader, .unlimited);
                                           ^
/home/andy/src/zig/lib/compiler/std-docs.zig:217:31: 0x117bc6f in serveSourcesTar (std-docs.zig)
        try archiver.writeFile(entry.path, &file_reader, stat.mtime);
                              ^
/home/andy/src/zig/lib/compiler/std-docs.zig:141:28: 0x117ccf3 in serveRequest (std-docs.zig)
        try serveSourcesTar(request, context);
                           ^
/home/andy/src/zig/lib/compiler/std-docs.zig:109:21: 0x117d695 in accept (std-docs.zig)
        serveRequest(&request, context) catch |err| {
                    ^
/home/andy/src/zig/lib/std/Thread.zig:510:13: 0x116f63a in callFn__anon_25881 (std.zig)
            @call(.auto, f, args);
            ^
/home/andy/src/zig/lib/std/Thread.zig:1382:30: 0x1168b9d in entryFn (std.zig)
                return callFn(f, self.fn_args);
                             ^
/home/andy/src/zig/lib/std/os/linux/x86_64.zig:119:5: 0x116f355 in clone (std.zig)
    asm volatile (
    ^
???:?:?: 0x0 in ??? (???)
fish: Job 1, 'ZIG_DEBUG_CMD=1 stage3/bin/zig …' terminated by signal SIGABRT (Abort)