Bug fix: allow checkers to have an empty exec.

plugin/syntastic.vim

@@ -19,7 +19,7 @@ if has('reltime')
     lockvar! g:_SYNTASTIC_START
 endif
 
-let g:_SYNTASTIC_VERSION = '3.7.0-229'
+let g:_SYNTASTIC_VERSION = '3.7.0-230'
 lockvar g:_SYNTASTIC_VERSION
 
 " Sanity checks {{{1

plugin/syntastic/checker.vim

@@ -32,6 +32,9 @@ function! g:SyntasticChecker.New(args, ...) abort " {{{2
         endif
     else
         let newObj._exec_default = get(a:args, 'exec', newObj._name)
+        if newObj._exec_default ==# ''
+            let newObj._exec_default = '<dummy>'
+        endif
         let prefix = 'SyntaxCheckers_' . newObj._filetype . '_' . newObj._name . '_'
 
         if has_key(a:args, 'enable')

syntax_checkers/vim/vimlint.vim

@@ -99,8 +99,7 @@ endfunction " }}}2
 
 call g:SyntasticRegistry.CreateAndRegisterChecker({
     \ 'filetype': 'vim',
-    \ 'name': 'vimlint',
-    \ 'exec': '' })
+    \ 'name': 'vimlint' })
 
 let &cpo = s:save_cpo
 unlet s:save_cpo