input/qobuz: parse and report message from error responses

src/input/plugins/QobuzLoginRequest.hxx

@@ -27,9 +27,11 @@
 #include "lib/yajl/Handle.hxx"
 
 #include <exception>
+#include <memory>
 #include <string>
 
 class CurlRequest;
+class QobuzErrorParser;
 
 class QobuzLoginHandler {
 public:
@@ -40,6 +42,8 @@ public:
 class QobuzLoginRequest final : CurlResponseHandler {
 	CurlRequest request;
 
+	std::unique_ptr<QobuzErrorParser> error_parser;
+
 	Yajl::Handle parser;
 
 	enum class State {