Update runtime files.
diff --git a/runtime/syntax/cpp.vim b/runtime/syntax/cpp.vim
index 53b6a51..ed38913 100644
--- a/runtime/syntax/cpp.vim
+++ b/runtime/syntax/cpp.vim
@@ -2,13 +2,16 @@
" Language: C++
" Current Maintainer: vim-jp (https://github.com/vim-jp/vim-cpp)
" Previous Maintainer: Ken Shan <ccshan@post.harvard.edu>
-" Last Change: 2019 Dec 18
+" Last Change: 2021 Jan 12
" quit when a syntax file was already loaded
if exists("b:current_syntax")
finish
endif
+" inform C syntax that the file was included from cpp.vim
+let b:filetype_in_cpp_family = 1
+
" Read the C syntax to start with
runtime! syntax/c.vim
unlet b:current_syntax