Allow overriding need_localtime for custom formatter

include/spdlog/pattern_formatter-inl.h

@@ -1081,6 +1081,11 @@ SPDLOG_INLINE void pattern_formatter::set_pattern(std::string pattern)
     compile_pattern_(pattern_);
 }
 
+SPDLOG_INLINE void pattern_formatter::need_localtime(bool need)
+{
+    need_localtime_ = need;
+}
+
 SPDLOG_INLINE std::tm pattern_formatter::get_time_(const details::log_msg &msg)
 {
     if (pattern_time_type_ == pattern_time_type::local)

include/spdlog/pattern_formatter.h

@@ -98,6 +98,7 @@ public:
         return *this;
     }
     void set_pattern(std::string pattern);
+    void need_localtime(bool need = true);
 
 private:
     std::string pattern_;