message: Log improvements
diff: @@ -51,6 +51,7 @@ using std::chrono::milliseconds;
  namespace LIEF {
  namespace logging {
  +// TODO(romain): Update when moving to C++17
  class Logger {
  public:
  Logger(const Logger&) = delete;
  @@ -69,8 +70,10 @@ class Logger {
  template <typename... Args>
  static void trace(const char *fmt, const Args &... args) {
  + if /* constexpr */ (lief_logging_support and lief_logging_debug) {
  Logger::instance().sink_->trace(fmt, args...);
  }
  + }
  template <typename... Args>
  static void debug(const char *fmt, const Args &... args) {
  @@ -107,7 +110,7 @@ class Logger {
  Logger& operator=(Logger&&);
  static void destroy(void);
  - static Logger* instance_;
  + /* inline */ static Logger* instance_;
  std::shared_ptr<spdlog::logger> sink_;
  };
  