Making vim-syntastic work with ebuilds

ebuild.vimrc

""" ebuild
augroup ebuild_vimrc
	autocmd BufRead,BufNewFile *.ebuild set filetype=ebuild
	" plugin
	autocmd FileType ebuild
				\ set statusline+=%#warningmsg# |
				\ set statusline+=%{SyntasticStatuslineFlag()} |
				\ set statusline+=%* |
				\ let g:syntastic_sh_shellcheck_args = '-s bash -e "SC2034,SC2016,SC2191,SC2037"' |
				\ let g:syntastic_always_populate_loc_list = 1 |
				\ let g:syntastic_auto_loc_list = 1 |
				\ let g:syntastic_check_on_open = 1 |
				\ let g:syntastic_check_on_wq = 0 |
				\ let b:auto_save = 1
augroup END