Function gtk_sys::gtk_file_chooser_native_new

pub unsafe extern "C" fn gtk_file_chooser_native_new(
    title: *const c_char, 
    parent: *mut GtkWindow, 
    action: GtkFileChooserAction, 
    accept_label: *const c_char, 
    cancel_label: *const c_char
) -> *mut GtkFileChooserNative

This is supported on crate feature v3_20 only.