feat: flatpak and flutter build

build.rs

@@ -105,6 +105,7 @@ fn main() {
     // there is problem with cfg(target_os) in build.rs, so use our workaround
     // let target_os = std::env::var("CARGO_CFG_TARGET_OS").unwrap();
     // if target_os == "android" || target_os == "ios" {
+    #[cfg(feature = "flutter")]
     gen_flutter_rust_bridge();
     //     return;
     // }