Apply a few clang-tidy cppcoreguidelines-* fixes

src/main.cpp

@@ -99,7 +99,7 @@ int main(int ac, char** av)
   // Block the signals we want to manage. They will be unblocked only during
   // the epoll_pwait or ppoll calls. This avoids some race conditions,
   // explained in man 2 pselect on linux
-  sigset_t mask;
+  sigset_t mask{};
   sigemptyset(&mask);
   sigaddset(&mask, SIGINT);
   sigaddset(&mask, SIGTERM);

src/network/poller.cpp

@@ -198,7 +198,7 @@ int Poller::poll(const std::chrono::milliseconds& timeout)
   static const size_t max_events = 12;
   struct epoll_event revents[max_events];
   // Unblock all signals, only during the epoll_pwait call
-  sigset_t empty_signal_set;
+  sigset_t empty_signal_set{};
   sigemptyset(&empty_signal_set);
   const int nb_events = ::epoll_pwait(this->epfd, revents, max_events, timeout.count(),
                                       &empty_signal_set);

src/network/tcp_client_socket_handler.cpp

@@ -35,7 +35,7 @@ void TCPClientSocketHandler::init_socket(const struct addrinfo* rp)
       // Convert the address from string format to a sockaddr that can be
       // used in bind()
       struct addrinfo* result;
-      struct addrinfo hints;
+      struct addrinfo hints{};
       memset(&hints, 0, sizeof(hints));
       hints.ai_flags = AI_NUMERICHOST;
       hints.ai_family = AF_UNSPEC;
@@ -161,14 +161,14 @@ void TCPClientSocketHandler::connect(const std::string& address, const std::stri
           this->local_port = static_cast<uint16_t>(-1);
           if (rp->ai_family == AF_INET6)
             {
-              struct sockaddr_in6 a;
+              struct sockaddr_in6 a{};
               socklen_t l = sizeof(a);
               if (::getsockname(this->socket, (struct sockaddr*)&a, &l) != -1)
                 this->local_port = ntohs(a.sin6_port);
             }
           else if (rp->ai_family == AF_INET)
             {
-              struct sockaddr_in a;
+              struct sockaddr_in a{};
               socklen_t l = sizeof(a);
               if (::getsockname(this->socket, (struct sockaddr*)&a, &l) != -1)
                 this->local_port = ntohs(a.sin_port);

src/utils/system.cpp

@@ -9,7 +9,7 @@ namespace utils
 {
 std::string get_system_name()
 {
-  struct utsname uts;
+  struct utsname uts{};
   const int res = ::uname(&uts);
   if (res == -1)
     {

src/xmpp/xmpp_parser.hpp

@@ -106,7 +106,7 @@ private:
   /**
    * Expat structure.
    */
-  XML_Parser parser;
+  XML_Parser parser{};
   /**
    * The current depth in the XML document
    */