Replace fmt::localtime with localtime_r

fmt::localtime was deprecated in fmt 11.2.0 and removed in fmt 12.0.0.
Replace with localtime_r, which is what fmt::localtime was implemented
with internally. The new implementation maintains identical behavior by
throwing a fmt::format_error exception when localtime_r() fails,
matching the original fmt::localtime() behavior.

See: https://github.com/fmtlib/fmt/releases/tag/12.0.0

Signed-off-by: Kefu Chai <tchaikov@gmail.com>

Author: tchaikov

src/logging.cpp

@@ -27,8 +27,12 @@ void logger_t::generate_common_prefix(std::string *str,
                                       fmt::text_style const &ts,
                                       char const *prefix) const
 {
-    *str += fmt::format("{:%Y-%m-%d %H:%M:%S}  ",
-                        fmt::localtime(std::time(nullptr)));
+    auto const now = std::time(nullptr);
+    std::tm tm_local;
+    if (!localtime_r(&now, &tm_local)) {
+        throw fmt::format_error("time_t value out of range");
+    }
+    *str += fmt::format("{:%F %T}  ", tm_local);
 
     if (m_current_level == log_level::debug) {
         *str += fmt::format(ts, "[{:02d}] ", this_thread_num);