parsing std::chrono::sys_time depends on time zone

[lenard-mosys]

Observed

With scnlib 4.0.1:

#include <chrono>
#include <fmt/chrono.h>
#include <iostream>

#include <scn/scan.h>
#include <scn/chrono.h>

int main() {
    const auto datetime = std::string_view("2025-02-05T16:00:01");
    using Time = std::chrono::sys_time<std::chrono::seconds>;
    Time tp;
    auto is = std::istringstream(std::string(datetime));
    is >> std::chrono::parse("%Y-%m-%dT%H:%M:%S", tp);
    if (is.fail()) { return 1; }
    std::cout << fmt::format("{0:%F}T{0:%T}\n", tp);
    std::cout << tp.time_since_epoch().count() << std::endl;

    auto result = scn::scan<Time>(datetime, "{:%Y-%m-%dT%H:%M:%S}");
    if (!result) { return 2; }
    std::cout << fmt::format("{0:%F}T{0:%T}\n", result->value());
    std::cout << result->value().time_since_epoch().count() << std::endl;

    return 0;
}

Run with TZ=America/New_York in the environment variables.

Output:

2025-02-05T16:00:01
1738771201
2025-02-05T21:00:01
1738789201

https://godbolt.org/z/E7e63G8bn

Expected

Parsing to not be dependent on local time zone, unless explicitly specified somehow.