fix(cli): keep default cc flags in build

cli/loader/build.rs

@@ -3,6 +3,10 @@ fn main() {
         "cargo:rustc-env=BUILD_TARGET={}",
         std::env::var("TARGET").unwrap()
     );
+    println!(
+        "cargo:rustc-env=BUILD_HOST={}",
+        std::env::var("HOST").unwrap()
+    );
 
     let emscripten_version = std::fs::read_to_string("emscripten-version").unwrap();
     println!("cargo:rustc-env=EMSCRIPTEN_VERSION={emscripten_version}");