Restore deleted code, it's going to be useful

Author: shana

src/GitHub.Api/Installer/ZipHelper.cs

@@ -118,6 +118,18 @@ public static void ExtractZipFile(string archive, string outFolder, Cancellation
                     {
                         Directory.CreateDirectory(directoryName);
                     }
+//#if !WINDOWS
+//                    if (Environment.OSVersion.Platform == PlatformID.Unix || Environment.OSVersion.Platform == PlatformID.MacOSX)
+//                    {
+//                        if (zipEntry.ExternalFileAttributes > 0)
+//                        {
+//                            int fd = Mono.Unix.Native.Syscall.open(fullZipToPath,
+//                                                                    Mono.Unix.Native.OpenFlags.O_CREAT | Mono.Unix.Native.OpenFlags.O_TRUNC,
+//                                                                    (Mono.Unix.Native.FilePermissions)zipEntry.ExternalFileAttributes);
+//                            Mono.Unix.Native.Syscall.close(fd);
+//                        }
+//                    }
+//#endif
 
                     // Unzip file in buffered chunks. This is just as fast as unpacking to a buffer the full size
                     // of the file, but does not waste memory.