🐛 fix native file sink lifecycle behavior

src/utils/file_backend_native.mbt

@@ -37,7 +37,7 @@ type NativeFileHandle
 #borrow(path, mode)
 extern "C" fn file_open_ffi(path : Bytes, mode : Bytes) -> NativeFileHandle = "fopen"
 
-extern "C" fn file_is_null_ffi(handle : NativeFileHandle) -> Bool = "moonbitlang_async_pointer_is_null"
+extern "C" fn file_is_null_ffi(handle : NativeFileHandle) -> Bool = "bitlogger_pointer_is_null"
 
 #borrow(buffer)
 extern "C" fn file_write_ffi(

src/utils/moon.pkg

@@ -7,6 +7,7 @@ import {
 }
 
 options(
+  "native-stub": [ "stub.c" ],
   targets: {
     "file_backend_native.mbt": [ "native", "llvm" ],
     "file_backend_stub.mbt": [ "js", "wasm", "wasm-gc" ],

src/utils/stub.c

@@ -0,0 +1,5 @@
+#include <stdint.h>
+
+int32_t bitlogger_pointer_is_null(void *ptr) {
+  return ptr == 0;
+}