commit https://github.com/vim/vim/commit/169ebb080454357279ad5ad21ac532deaec605e8 Author: Bram Moolenaar <Bram@vim.org> Date: Wed Sep 7 23:32:23 2016 +0200 patch 7.4.2344 Problem: The "Reading from channel output..." message can be unwanted. Appending to a buffer leaves an empty first line behind. Solution: Add the "out_msg" and "err_msg" options. Writing the first line overwrites the first, empty line.

" 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$*\ \"%:p\"\ -o\ \"%:p:r.$*\"