Improve guard so it works for no eof new line

syntax/xdc.vim

@@ -1,4 +1,5 @@
 if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'xdc') == -1
+
 " Vim syntax file
 " Language:     XDC - Xilinx Design Constraints
 " Author:       Amal Khailtash <amal.khailtash@gmail.com>
@@ -192,4 +193,5 @@ highligh default link xdcFlags                                Special
 let b:current_syntax = "xdc"
 
 " vim: fileformat=unix tabstop=2 shiftwidth=2 expandtab
+
 endif