for building (but not shipping) C API we need truffle.h

Author: timfel

mx.graalpython/mx_graalpython.py

@@ -1156,6 +1156,7 @@ def _prepare_headers(self):
             if os.path.exists(target_dir):
                 shutil.rmtree(target_dir)
             shutil.copytree(os.path.join(self.src_dir(), "include"), target_dir)
+            shutil.copy(os.path.join(mx.dependency("SULONG_LEGACY").get_output(), "include", "truffle.h"), target_dir)
 
     def build(self):
         self._prepare_headers()