Handle NULL return from SDL_DBus_GetContext()

src/thread/pthread/SDL_systhread.c

@@ -200,7 +200,7 @@ rtkit_initialize()
     SDL_DBusContext *dbus = SDL_DBus_GetContext();
 
     /* Try getting minimum nice level: this is often greater than PRIO_MIN (-20). */
-    if (!SDL_DBus_QueryPropertyOnConnection(dbus->system_conn, RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MinNiceLevel",
+    if (!dbus || !SDL_DBus_QueryPropertyOnConnection(dbus->system_conn, RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MinNiceLevel",
                                             DBUS_TYPE_INT32, &rtkit_min_nice_level)) {
         rtkit_min_nice_level = -20;
     }
@@ -218,13 +218,12 @@ rtkit_setpriority(pid_t thread, int nice_level)
     if (si32 < rtkit_min_nice_level)
         si32 = rtkit_min_nice_level;
 
-    if (!SDL_DBus_CallMethodOnConnection(dbus->system_conn,
+    if (!dbus || !SDL_DBus_CallMethodOnConnection(dbus->system_conn,
             RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MakeThreadHighPriority",
             DBUS_TYPE_UINT64, &ui64, DBUS_TYPE_INT32, &si32, DBUS_TYPE_INVALID,
             DBUS_TYPE_INVALID)) {
         return SDL_FALSE;
     }
-
     return SDL_TRUE;
 }