Port root authentication from AppImage/AppImageKit#364

Thanks @abhay44

Author: probonopd

main.vala

@@ -8,6 +8,23 @@ static HeaderBar header_bar; // Too new to assume it is there?
 
 static string selected_file;
 
+static string root(){
+ 
+var a = Posix.system("pkexec --disable-internal-agent echo hello to appimages");
+if (a == 32256){
+return "false";
+}
+else{
+return "true";
+}
+
+}
+static void root_run(){
+if(root() == "false"){
+Posix.exit(0);
+}
+}
+
 /* Open file */
 static void open_file(string filename) {
  selected_file = filename;
@@ -46,6 +63,7 @@ static void on_about_clicked() {
 }
 
 static void main (string[] args) {
+root_run();
 init (ref args);
  if(args.length > 1){
  open_file(args[1]);