internal: use native api in c_runtime

sync_io/moon.pkg.json

@@ -8,11 +8,7 @@
     "targets": {
         "sync_io_wasm.mbt": ["wasm", "wasm-gc"],
         "sync_io_js.mbt": ["js"],
-        "sync_io_native.mbt": ["native"]
-    },
-    "link": {
-        "native": {
-           "cc-flags": "./sync_io/native_stub.c"
-        }
+        "sync_io_native.mbt": ["native"],
+        "util.mbt": ["wasm", "wasm-gc"]
     }
 }

sync_io/sync_io.mbt

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 ///|
-type! IOError {
+pub type! IOError {
   NotFound(String)
 }
 

sync_io/sync_io_native.mbt

@@ -20,7 +20,7 @@ fn read_file_to_bytes_internal(path : String) -> Bytes! {
 }
 
 ///|
-extern "C" fn read_file_to_bytes_ffi(path : Bytes) -> Bytes = "read_file_to_bytes"
+fn read_file_to_bytes_ffi(path : Bytes) -> Bytes = "$moonbit.read_file_to_bytes"
 
 ///|
 fn write_bytes_to_file_internal(path : String, content : Bytes) -> Unit {
@@ -29,15 +29,15 @@ fn write_bytes_to_file_internal(path : String, content : Bytes) -> Unit {
 }
 
 ///|
-extern "C" fn write_bytes_to_file_ffi(path : Bytes, content : Bytes) = "write_bytes_to_file"
+fn write_bytes_to_file_ffi(path : Bytes, content : Bytes) = "$moonbit.write_bytes_to_file"
 
 ///|
 fn path_exists_internal(path : String) -> Bool {
   path_exists_ffi(mbt_string_to_utf8_bytes(path, true)) == 0
 }
 
 ///|
-extern "C" fn path_exists_ffi(path : Bytes) -> Int = "path_exists"
+fn path_exists_ffi(path : Bytes) -> Int = "$moonbit.path_exists"
 
 ///|
 fn mbt_string_to_utf8_bytes(str : String, is_c_str : Bool) -> Bytes {