FIX #344 - Add options to Perl linter

Conflicts:
	doc/ale.txt

ale_linters/perl/perl.vim

@@ -1,6 +1,22 @@
 " Author: Vincent Lequertier <https://github.com/SkySymbol>
 " Description: This file adds support for checking perl syntax
 
+let g:ale_perl_perl_executable =
+\   get(g:, 'ale_perl_perl_executable', 'perl')
+
+let g:ale_perl_perl_options =
+\   get(g:, 'ale_perl_perl_options', '-X -c -Mwarnings -Ilib')
+
+function! ale_linters#perl#perl#GetExecutable(buffer) abort
+    return g:ale_perl_perl_executable
+endfunction
+
+function! ale_linters#perl#perl#GetCommand(buffer) abort
+    return ale_linters#perl#perl#GetExecutable(a:buffer)
+    \   . ' ' . g:ale_perl_perl_options
+    \   . ' %t'
+endfunction
+
 function! ale_linters#perl#perl#Handle(buffer, lines) abort
     let l:pattern = '\(.\+\) at \(.\+\) line \(\d\+\)'
     let l:output = []
@@ -32,8 +48,8 @@ endfunction
 
 call ale#linter#Define('perl', {
 \   'name': 'perl',
-\   'executable': 'perl',
+\   'executable_callback': 'ale_linters#perl#perl#GetExecutable',
 \   'output_stream': 'both',
-\   'command': 'perl -X -c -Mwarnings -Ilib',
+\   'command_callback': 'ale_linters#perl#perl#GetCommand',
 \   'callback': 'ale_linters#perl#perl#Handle',
 \})