Improve guard to support concatenated files

indent/cmake.vim

@@ -1,7 +1,4 @@
-if exists('g:polyglot_disabled') && index(g:polyglot_disabled, 'cmake') != -1
-  finish
-endif
-
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'cmake') == -1
 " Vim indent file
 " Language:     CMake (ft=cmake)
 " Author:       Andy Cedilnik <andy.cedilnik@kitware.com>
@@ -91,3 +88,4 @@ endfun
 
 let &cpo = s:keepcpo
 unlet s:keepcpo
+endif