removed another positional refs in printf format

src/video_rxtx/rtp.cpp

@@ -260,20 +260,20 @@ void rtp_video_rxtx::display_buf_increase_warning(int size)
 #endif
         log_msg(
             LOG_LEVEL_INFO,
-            "Please set " SYSCTL_ENTRY " value to %1$d or greater (see also\n"
+            "Please set " SYSCTL_ENTRY " value to %d or greater (see also\n"
             "https://github.com/CESNET/UltraGrid/wiki/OS-Setup-UltraGrid):\n"
 #ifdef __APPLE__
-            "\tsysctl -w kern.ipc.maxsockbuf=%2$d\n"
+            "\tsysctl -w kern.ipc.maxsockbuf=%d\n"
 #endif
-            "\tsysctl -w " SYSCTL_ENTRY "=%1$d\n"
+            "\tsysctl -w " SYSCTL_ENTRY "=%d\n"
             "To make this persistent, add these options (key=value) to "
             "/etc/sysctl.d/60-ultragrid.conf\n"
             "\n***\n\n",
-            size
+            size,
 #ifdef __APPLE__
-            ,
-            size * 4
+            size * 4,
 #endif /* __APPLE__ */
+            size
         );
 #undef SYSCTL_ENTRY
 }