commit https://github.com/vim/vim/commit/f71d7b9ee5ceba75f70c30845332ddd728fd16c6 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Aug 9 22:14:05 2016 +0200 patch 7.4.2189 Problem: Cannot detect encoding in a fifo. Solution: Extend the stdin way of detecting encoding to fifo. Add a test for detecting encoding on stdin and fifo. (Ken Takata)

" Vim compiler file
" Compiler:     ATT dot
" Maintainer:	Marcos Macedo <bar4ka@bol.com.br>
" Last Change:	2004 May 16

if exists("current_compiler")
  finish
endif
let current_compiler = "dot"

if exists(":CompilerSet") != 2		" older Vim always used :setlocal
  command -nargs=* CompilerSet setlocal <args>
endif

CompilerSet makeprg=dot\ -T$*\ \"%:p\"\ -o\ \"%:p:r.$*\"