Removed syntastic and replaced it with ale

Read more here:
https://github.com/w0rp/ale

sources_non_forked/ale/ale_linters/xml/xmllint.vim

@@ -0,0 +1,69 @@
+" Author: q12321q <q12321q@gmail.com>
+" Description: This file adds support for checking XML code with xmllint.
+
+" CLI options
+let g:ale_xml_xmllint_executable = get(g:, 'ale_xml_xmllint_executable', 'xmllint')
+let g:ale_xml_xmllint_options = get(g:, 'ale_xml_xmllint_options', '')
+
+function! ale_linters#xml#xmllint#GetExecutable(buffer) abort
+    return ale#Var(a:buffer, 'xml_xmllint_executable')
+endfunction
+
+function! ale_linters#xml#xmllint#GetCommand(buffer) abort
+    return ale#Escape(ale_linters#xml#xmllint#GetExecutable(a:buffer))
+    \   . ' ' . ale#Var(a:buffer, 'xml_xmllint_options')
+    \   . ' --noout -'
+endfunction
+
+function! ale_linters#xml#xmllint#Handle(buffer, lines) abort
+    " Matches patterns lines like the following:
+    " file/path:123: error level : error message
+    let l:pattern_message = '\v^([^:]+):(\d+):\s*(([^:]+)\s*:\s+.*)$'
+
+    " parse column token line like that:
+    " file/path:123: parser error : Opening and ending tag mismatch: foo line 1 and bar
+    " </bar>
+    "       ^
+    let l:pattern_column_token = '\v^\s*\^$'
+
+    let l:output = []
+
+    for l:line in a:lines
+
+        " Parse error/warning lines
+        let l:match_message = matchlist(l:line, l:pattern_message)
+        if !empty(l:match_message)
+          let l:line = l:match_message[2] + 0
+          let l:type = l:match_message[4] =~? 'warning' ? 'W' : 'E'
+          let l:text = l:match_message[3]
+
+          call add(l:output, {
+          \   'lnum': l:line,
+          \   'text': l:text,
+          \   'type': l:type,
+          \})
+
+          continue
+        endif
+
+        " Parse column position
+        let l:match_column_token = matchlist(l:line, l:pattern_column_token)
+        if !empty(l:output) && !empty(l:match_column_token)
+          let l:previous = l:output[len(l:output) - 1]
+          let l:previous['col'] = len(l:match_column_token[0])
+
+          continue
+        endif
+
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('xml', {
+\   'name': 'xmllint',
+\   'output_stream': 'stderr',
+\   'executable_callback': 'ale_linters#xml#xmllint#GetExecutable',
+\   'command_callback': 'ale_linters#xml#xmllint#GetCommand',
+\   'callback': 'ale_linters#xml#xmllint#Handle',
+\ })