Use std::localtime() instead of plain C localtime()

src/format_time_summary.cpp

@@ -22,14 +22,14 @@ namespace utils {
 
 std::string format_time_summary(std::time_t t) {
 	std::time_t curtime = std::time(nullptr);
-	const struct tm* timeptr = localtime(&curtime);
+	const struct tm* timeptr = std::localtime(&curtime);
 	if(timeptr == nullptr) {
 		return "";
 	}
 
 	const struct tm current_time = *timeptr;
 
-	timeptr = localtime(&t);
+	timeptr = std::localtime(&t);
 	if(timeptr == nullptr) {
 		return "";
 	}

src/gui/dialogs/debug_clock.cpp

@@ -174,7 +174,7 @@ debug_clock::time::time() : hour(0), minute(0), second(0), millisecond(0)
 void debug_clock::time::set_current_time()
 {
 	std::time_t now = ::std::time(nullptr);
-	tm* stamp = localtime(&now);
+	tm* stamp = std::localtime(&now);
 
 	hour = stamp->tm_hour;
 	minute = stamp->tm_min;

src/save_index.cpp

@@ -213,7 +213,7 @@ const config& save_info::summary() const
 
 std::string save_info::format_time_local() const
 {
-	if(tm* tm_l = localtime(&modified())) {
+	if(tm* tm_l = std::localtime(&modified())) {
 		const std::string format = preferences::use_twelve_hour_clock_format()
 			? _("%a %b %d %I:%M %p %Y")
 			: _("%a %b %d %H:%M %Y");

src/server/ban.cpp

@@ -330,7 +330,7 @@ static lg::log_domain log_server("server");
 
 		if (duration.substr(0,4) == "TIME") {
 			struct tm* loc;
-			loc = localtime(time);
+			loc = std::localtime(time);
 
 			std::size_t number = 0;
 			for (std::string::const_iterator i = duration.begin() + 4;