message: Fix build with ASAN version of Clang
diff: @@ -241,8 +241,9 @@ void logger::init(actor_system_config& cfg) {
  void logger::render_fun_prefix(std::ostream& out, const char* pretty_fun) {
  auto first = pretty_fun;
  // set end to beginning of arguments
  - auto last = std::find_if(first, static_cast<const char*>(nullptr),
  - [](char x) { return x == '(' || x == '\0'; });
  + const char* last = strchr(pretty_fun, '(');
  + if (last == nullptr)
  + return;
  auto strsize = static_cast<size_t>(last - first);
  auto jump_to_next_whitespace = [&] {
  // leave `first` unchanged if no whitespaces is present,
  @@ -274,16 +275,15 @@ void logger::render_fun_prefix(std::ostream& out, const char* pretty_fun) {
  void logger::render_fun_name(std::ostream& out, const char* pretty_fun) {
  // Find the end of the function name by looking for the opening parenthesis
  // trailing it.
  - const char* e = nullptr; // safe, because pretty_fun is null-terminated
  - auto i = std::find_if(pretty_fun, e,
  - [](char x) { return x == '(' || x == '\0'; });
  - if (*i == '\0')
  + CAF_ASSERT(pretty_fun != nullptr);
  + const char* e = strchr(pretty_fun, '(');
  + if (e == nullptr)
  return;
  /// Now look for the beginning of the function name.
  using rev_iter = std::reverse_iterator<const char*>;
  - auto b = std::find_if(rev_iter(i), rev_iter(pretty_fun),
  + auto b = std::find_if(rev_iter(e), rev_iter(pretty_fun),
  [](char x) { return x == ':' || x == ' '; });
  - out.write(b.base(), i - b.base());
  + out.write(b.base(), e - b.base());
  }
  void logger::render_time_diff(std::ostream& out, timestamp t0, timestamp tn) {
  