diff --git a/src/mhd2/daemon_add_conn.c b/src/mhd2/daemon_add_conn.c
index 97c65514..15a9986e 100644
--- a/src/mhd2/daemon_add_conn.c
+++ b/src/mhd2/daemon_add_conn.c
@@ -470,11 +470,11 @@ new_connection_process_ (struct MHD_Daemon *restrict daemon,
 #ifdef mhd_DEBUG_CONN_ADD_CLOSE
   if (MHD_SC_OK == res)
     fprintf (stderr,
-             "&&&  Added new connection, FD: %llu\n",
+             "&&&  Added new connection, FD: %2llu\n",
              (unsigned long long) connection->sk.fd);
   else
     fprintf (stderr,
-             "&&& Failed add connection, FD: %llu -> %u\n",
+             "&&& Failed add connection, FD: %2llu -> %u\n",
              (unsigned long long) connection->sk.fd,
              (unsigned int) res);
 #endif /* mhd_DEBUG_CONN_ADD_CLOSE */
@@ -1114,7 +1114,7 @@ mhd_conn_close_final (struct MHD_Connection *restrict c)
   mhd_socket_close (c->sk.fd);
 #ifdef mhd_DEBUG_CONN_ADD_CLOSE
   fprintf (stderr,
-           "&&&     Closed connection, FD: %llu\n",
+           "&&&     Closed connection, FD: %2llu\n",
            (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_CONN_ADD_CLOSE */
 
diff --git a/src/mhd2/daemon_event_update.c b/src/mhd2/daemon_event_update.c
index 7f4f1894..b65b1d6e 100644
--- a/src/mhd2/daemon_event_update.c
+++ b/src/mhd2/daemon_event_update.c
@@ -77,19 +77,19 @@ MHD_daemon_event_update (
       break;
     case mhd_SOCKET_REL_MARKER_ITC:
       fprintf (stderr,
-               "### MHD_daemon_event_update(daemon, [ITC:  %llu], %s)\n",
+               "### MHD_daemon_event_update(daemon, [ITC:  %2llu], %s)\n",
                (unsigned long long) mhd_itc_r_fd (daemon->threading.itc),
                state_str);
       break;
     case mhd_SOCKET_REL_MARKER_LISTEN:
       fprintf (stderr,
-               "### MHD_daemon_event_update(daemon, [lstn: %llu], %s)\n",
+               "### MHD_daemon_event_update(daemon, [lstn: %2llu], %s)\n",
                (unsigned long long) daemon->net.listen.fd,
                state_str);
       break;
     default:
       fprintf (stderr,
-               "### MHD_daemon_event_update(daemon, [conn: %llu], %s)\n",
+               "### MHD_daemon_event_update(daemon, [conn: %2llu], %s)\n",
                (unsigned long long)
                (((struct MHD_Connection *) ecb_cntx)->sk.fd),
                state_str);
diff --git a/src/mhd2/events_process.c b/src/mhd2/events_process.c
index b9d6a829..340f85b4 100644
--- a/src/mhd2/events_process.c
+++ b/src/mhd2/events_process.c
@@ -70,7 +70,7 @@
 
 #include "mhd_public_api.h"
 
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
 /**
  * Debug-printf request of FD polling/monitoring
  * @param fd_name the name of FD ("ITC", "lstn" or "conn")
@@ -92,7 +92,7 @@ mhd_dbg_print_fd_mon_req (const char *fd_name,
   state_str[4] = e_ready ? 'E' : '-';
 
   fprintf (stderr,
-           "### Set FD watching: %4s [%llu] for %s\n",
+           "### Set FD watching: %4s [%2llu] for %s\n",
            fd_name,
            (unsigned long long) fd,
            state_str);
@@ -120,7 +120,7 @@ dbg_print_fd_state_update (const char *fd_name,
   state_str[4] = e_ready ? 'E' : '-';
 
   fprintf (stderr,
-           "### FD state update: %4s [%llu]  -> %s\n",
+           "### FD state update: %4s [%2llu]  -> %s\n",
            fd_name,
            (unsigned long long) fd,
            state_str);
@@ -128,8 +128,8 @@ dbg_print_fd_state_update (const char *fd_name,
 
 
 #else  /* ! mhd_DEBUG_POLLING_FDS */
-#  defined dbg_print_fd_state_update (fd_n,fd,r_ready,w_ready,e_ready) ((void) 0 \
-                                                                        )
+#  define dbg_print_fd_state_update(fd_n,fd,r_ready,w_ready,e_ready) \
+        ((void) 0)
 #endif /* ! mhd_DEBUG_POLLING_FDS */
 
 /**
@@ -207,7 +207,7 @@ start_resuming_connection (struct MHD_Connection *restrict c,
   mhd_assert (c->suspended);
 #ifdef mhd_DEBUG_SUSPEND_RESUME
   fprintf (stderr,
-           "%%%%%%   Resuming connection, FD: %llu\n",
+           "%%%%%%   Resuming connection, FD: %2llu\n",
            (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
   c->suspended = false;
@@ -1078,7 +1078,7 @@ get_all_net_updates_by_select_and_resume_conn (struct MHD_Daemon *restrict d,
   tmvl.tv_usec = (int) ((max_wait % 1000) * 1000);
 #endif
 
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
   fprintf (stderr,
            "### (Starting) select(%d, rfds, wfds, efds, [%llu, %llu])...\n",
            max_socket + 1,
@@ -1090,7 +1090,7 @@ get_all_net_updates_by_select_and_resume_conn (struct MHD_Daemon *restrict d,
                        d->events.data.select.wfds,
                        d->events.data.select.efds,
                        &tmvl);
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
   fprintf (stderr,
            "### (Finished) select(%d, rfds, wfds, efds, ->[%llu, %llu]) -> "
            "%d\n",
@@ -1383,7 +1383,7 @@ static MHD_FN_PAR_NONNULL_ (1) bool
 get_all_net_updates_by_poll (struct MHD_Daemon *restrict d,
                              bool listen_only)
 {
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
 #  ifdef MHD_SOCKETS_KIND_POSIX
   static const char poll_fn_name[] = "poll";
 #  else  /* MHD_SOCKETS_KIND_WINSOCK */
@@ -1401,7 +1401,7 @@ get_all_net_updates_by_poll (struct MHD_Daemon *restrict d,
   // TODO: handle empty list situation
   max_wait = get_max_wait (d); // TODO: use correct timeout value
 
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
   fprintf (stderr,
            "### (Starting) %s(fds, %u, %d)...\n",
            poll_fn_name,
@@ -1411,7 +1411,7 @@ get_all_net_updates_by_poll (struct MHD_Daemon *restrict d,
   num_events = mhd_poll (d->events.data.poll.fds,
                          num_fds,
                          max_wait); // TODO: use correct timeout value
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
   fprintf (stderr,
            "### (Finished) %s(fds, %u, %d) -> %d\n",
            poll_fn_name,
@@ -1580,7 +1580,7 @@ get_all_net_updates_by_epoll (struct MHD_Daemon *restrict d)
   max_wait = get_max_wait (d); // TODO: use correct timeout value
   do
   {
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
     fprintf (stderr,
              "### (Starting) epoll_wait(%d, events, %d, %d)...\n",
              d->events.data.epoll.e_fd,
@@ -1591,7 +1591,7 @@ get_all_net_updates_by_epoll (struct MHD_Daemon *restrict d)
                              d->events.data.epoll.events,
                              (int) d->events.data.epoll.num_elements,
                              max_wait);
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
     fprintf (stderr,
              "### (Finished) epoll_wait(%d, events, %d, %d) -> %d\n",
              d->events.data.epoll.e_fd,
@@ -1758,7 +1758,7 @@ MHD_daemon_process_reg_events (struct MHD_Daemon *MHD_RESTRICT daemon,
   enum MHD_StatusCode res;
 #ifdef mhd_DEBUG_POLLING_FDS
   fprintf (stderr,
-           "### (Started)  MHD_daemon_process_reg_events(daemon, [%s])...\n",
+           "### (Starting) MHD_daemon_process_reg_events(daemon, [%s])...\n",
            (NULL != next_max_wait) ? "non-NULL" : "NULL");
 #endif
   res = process_reg_events_int (daemon,
diff --git a/src/mhd2/extr_events_funcs.h b/src/mhd2/extr_events_funcs.h
index f89eac07..40c892cb 100644
--- a/src/mhd2/extr_events_funcs.h
+++ b/src/mhd2/extr_events_funcs.h
@@ -112,7 +112,7 @@ mhd_daemon_extr_event_reg (struct MHD_Daemon *d,
     break;
   }
   fprintf (stderr,
-           "### %s callback (cls, [%s %llu], %s, 0x%08llX, ptr) "
+           "### %s callback (cls, [%s %2llu], %s, 0x%08llX, ptr) "
            "-> 0x%08llX\n",
            reg_type,
            fd_rel,
diff --git a/src/mhd2/mhd_dbg_print.h b/src/mhd2/mhd_dbg_print.h
index ea7e330a..d8cf159e 100644
--- a/src/mhd2/mhd_dbg_print.h
+++ b/src/mhd2/mhd_dbg_print.h
@@ -35,7 +35,7 @@
 #endif /* mhd_DEBUG_POLLING_FDS */
 
 
-#if mhd_DEBUG_POLLING_FDS
+#ifdef mhd_DEBUG_POLLING_FDS
 /**
  * Debug-printf request of FD polling/monitoring
  * @param fd_name the name of FD ("ITC", "lstn" or "conn")
@@ -54,7 +54,7 @@ mhd_dbg_print_fd_mon_req (const char *fd_name,
 MHD_FN_PAR_NONNULL_ALL_;
 
 #else  /* ! mhd_DEBUG_POLLING_FDS */
-#  define dbg_print_fd_state_update(fd_n,fd,r_ready,w_ready,e_ready) ((void) 0)
+#  define mhd_dbg_print_fd_mon_req(fd_n,fd,r_ready,w_ready,e_ready) ((void) 0)
 #endif /* ! mhd_DEBUG_POLLING_FDS */
 
 
diff --git a/src/mhd2/request_resume.c b/src/mhd2/request_resume.c
index 47531394..cdb1a647 100644
--- a/src/mhd2/request_resume.c
+++ b/src/mhd2/request_resume.c
@@ -51,7 +51,7 @@ MHD_request_resume (struct MHD_Request *request)
   {
 #ifdef mhd_DEBUG_SUSPEND_RESUME
     fprintf (stderr,
-             "%%%%%% Requested conn resume, FD: %llu -> "
+             "%%%%%% Requested conn resume, FD: %2llu -> "
              "failed as not suspended\n",
              (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
@@ -60,7 +60,7 @@ MHD_request_resume (struct MHD_Request *request)
   c->resuming = true;
 #ifdef mhd_DEBUG_SUSPEND_RESUME
   fprintf (stderr,
-           "%%%%%% Requested conn resume, FD: %llu\n",
+           "%%%%%% Requested conn resume, FD: %2llu\n",
            (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
   d->threading.resume_requested = true;
diff --git a/src/mhd2/stream_funcs.c b/src/mhd2/stream_funcs.c
index bf1772b3..59346a2e 100644
--- a/src/mhd2/stream_funcs.c
+++ b/src/mhd2/stream_funcs.c
@@ -1030,7 +1030,7 @@ mhd_conn_pre_clean (struct MHD_Connection *restrict c)
 {
 #ifdef mhd_DEBUG_CONN_ADD_CLOSE
   fprintf (stderr,
-           "&&&    Closing connection, FD: %llu\n",
+           "&&&    Closing connection, FD: %2llu\n",
            (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_CONN_ADD_CLOSE */
 
diff --git a/src/mhd2/stream_process_request.c b/src/mhd2/stream_process_request.c
index b6e87c2f..06298053 100644
--- a/src/mhd2/stream_process_request.c
+++ b/src/mhd2/stream_process_request.c
@@ -3008,7 +3008,7 @@ mhd_stream_call_app_request_cb (struct MHD_Connection *restrict c)
     c->suspended = true;
 #ifdef mhd_DEBUG_SUSPEND_RESUME
     fprintf (stderr,
-             "%%%%%% Suspending connection, FD: %llu\n",
+             "%%%%%% Suspending connection, FD: %2llu\n",
              (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
     c->rq.app_act.head_act.act = mhd_ACTION_NO_ACTION;
@@ -3075,7 +3075,7 @@ mhd_stream_process_upload_action (struct MHD_Connection *restrict c,
     c->suspended = true;
 #ifdef mhd_DEBUG_SUSPEND_RESUME
     fprintf (stderr,
-             "%%%%%% Suspending connection, FD: %llu\n",
+             "%%%%%% Suspending connection, FD: %2llu\n",
              (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
     memset (&(c->rq.app_act.upl_act), 0, sizeof(c->rq.app_act.upl_act));
diff --git a/src/mhd2/stream_process_states.c b/src/mhd2/stream_process_states.c
index 3afe3b06..d33dcc84 100644
--- a/src/mhd2/stream_process_states.c
+++ b/src/mhd2/stream_process_states.c
@@ -195,7 +195,7 @@ finish_resume (struct MHD_Connection *restrict c)
 
 #ifdef mhd_DEBUG_SUSPEND_RESUME
   fprintf (stderr,
-           "%%%%%%    Resumed connection, FD: %llu\n",
+           "%%%%%%    Resumed connection, FD: %2llu\n",
            (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
   mhd_assert (! c->suspended);
@@ -537,7 +537,7 @@ mhd_conn_process_data (struct MHD_Connection *restrict c)
     mhd_conn_remove_from_timeout_lists (c);
 #ifdef mhd_DEBUG_SUSPEND_RESUME
     fprintf (stderr,
-             "%%%%%%  Connection suspended, FD: %llu\n",
+             "%%%%%%  Connection suspended, FD: %2llu\n",
              (unsigned long long) c->sk.fd);
 #endif /* mhd_DEBUG_SUSPEND_RESUME */
     return true;