Skip encoder reprobing if no GPU changes have occurred

src/platform/common.h

@@ -558,6 +558,13 @@ namespace platf {
   std::vector<std::string>
   display_names(mem_type_e hwdevice_type);
 
+  /**
+   * @brief Returns if GPUs/drivers have changed since the last call to this function.
+   * @return `true` if a change has occurred or if it is unknown whether a change occurred.
+   */
+  bool
+  needs_encoder_reenumeration();
+
   boost::process::child
   run_command(bool elevated, bool interactive, const std::string &cmd, boost::filesystem::path &working_dir, const boost::process::environment &env, FILE *file, std::error_code &ec, boost::process::group *group);