Update runtime files.
diff --git a/runtime/ftplugin/c.vim b/runtime/ftplugin/c.vim
index 371a78c..70e54b3 100644
--- a/runtime/ftplugin/c.vim
+++ b/runtime/ftplugin/c.vim
@@ -1,7 +1,7 @@
" Vim filetype plugin file
" Language: C
" Maintainer: Bram Moolenaar <Bram@vim.org>
-" Last Change: 2017 Sep 28
+" Last Change: 2020 Feb 01
" Only do this when not done yet for this buffer
if exists("b:did_ftplugin")
@@ -15,12 +15,16 @@
let s:cpo_save = &cpo
set cpo-=C
-let b:undo_ftplugin = "setl fo< com< ofu< | if has('vms') | setl isk< | endif"
+let b:undo_ftplugin = "setl fo< com< ofu< cms< def< inc< | if has('vms') | setl isk< | endif"
" Set 'formatoptions' to break comment lines but not other lines,
" and insert the comment leader when hitting <CR> or using "o".
setlocal fo-=t fo+=croql
+" These options have the right value as default, but the user may have
+" overruled that.
+setlocal commentstring& define& include&
+
" Set completion with CTRL-X CTRL-O to autoloaded function.
if exists('&ofu')
setlocal ofu=ccomplete#Complete