Add question box on PrusaSlicer start to accept detected CA store..

Fix compile

src/slic3r/Utils/Http.hpp

@@ -100,6 +100,10 @@ public:
 
 	// Tells whether current backend supports seting up a CA file using ca_file()
 	static bool ca_file_supported();
+    
+    // Return empty string on success or error message on fail.
+    static std::string tls_global_init();
+    static std::string tls_system_cert_store();
 
 	// converts the given string to an url_encoded_string
 	static std::string url_encode(const std::string &str);