Fix #257 in preparation for #427, standardise options with fallbacks, and make it so every value can be computed dynamically

ale_linters/erlang/erlc.vim

@@ -5,6 +5,7 @@ let g:ale_erlang_erlc_options = get(g:, 'ale_erlang_erlc_options', '')
 function! ale_linters#erlang#erlc#GetCommand(buffer) abort
     let l:output_file = tempname()
     call ale#engine#ManageFile(a:buffer, l:output_file)
+
     return 'erlc -o ' . fnameescape(l:output_file) . ' ' . g:ale_erlang_erlc_options . ' %t'
 endfunction