fix: keep original source tree when symlink into ext_include_dir

foreign_cc/private/framework.bzl

@@ -749,13 +749,23 @@ def _symlink_contents_to_dir(dir_name, files_list):
         path = _file_path(file).strip()
         if path:
             lines.append("##symlink_contents_to_dir## \
-$$EXT_BUILD_ROOT$$/{} $$EXT_BUILD_DEPS$$/{} True".format(path, dir_name))
+$$EXT_BUILD_ROOT$$/{} $$EXT_BUILD_DEPS$$/{} True".format(path, _get_dir_name(dir_name, file)))
 
     return lines
 
 def _file_path(file):
     return file if type(file) == "string" else file.path
 
+def _get_dir_name(dir, file):
+    if dir == "include":
+        if type(file) == "File" and file.owner != None and file.owner.package != "":
+            workspace_root = file.owner.workspace_root
+            path = "/".join(file.path.split("/")[:-1])
+            prefix = "{}/".format(workspace_root)
+            if path.startswith(prefix):
+                return "{}/{}".format(dir, path.removeprefix(prefix))
+    return dir
+
 _FORBIDDEN_FOR_FILENAME = ["\\", "/", ":", "*", "\"", "<", ">", "|"]
 
 def _check_file_name(var):