To turn off expandtab for editing makefiles, put the following in your vimrc:
autocmd FileType make setlocal noexpandtab

I already put the following in my vimrc,but it didn't work when editing makefile.Vim still change tab into spaces.
Here is my vimrc,is there anything wrong ?



set nocompatible
source $VIMRUNTIME/vimrc_example.vim
source $VIMRUNTIME/mswin.vim
"behave mswin
syntax on
set expandtab
set tabstop=4
set shiftwidth=4
autocmd FileType make setlocal noexpandtab
set autoindent
set cindent
set nu
set diffexpr=MyDiff()
set nobackup
let &termencoding=&encoding

Anyone can help me.
Thank you.

don't know about your autocmd, but replacing

set ts=4
set sw=4
set expandtab

with

let _curfile = expand("%:t")
if _curfile =~ "Makefile" || _curfile =~ "makefile" || _curfile =~ ".*\.mk"
set noexpandtab
else
set expandtab
set tabstop=4
set shiftwidth=4
endif


seems to work.

source: http://ppadala.net/blog/tag/tips/