diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 01e982f..e205be7 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -862,6 +862,7 @@
 extern cpp_buffer *cpp_get_buffer (cpp_reader *);
 extern struct _cpp_file *cpp_get_file (cpp_buffer *);
 extern cpp_buffer *cpp_get_prev (cpp_buffer *);
+extern void cpp_clear_file_cache (cpp_reader *);
 
 /* In cpppch.c */
 struct save_macro_data;