Updated runtime files.

runtime/syntax/synload.vim

@@ -1,6 +1,6 @@
 " Vim syntax support file
 " Maintainer:	Bram Moolenaar <Bram@vim.org>
-" Last Change:	2012 Sep 25
+" Last Change:	2016 Nov 04
 
 " This file sets up for syntax highlighting.
 " It is loaded from "syntax.vim" and "manual.vim".
@@ -69,8 +69,11 @@ au Syntax c,cpp,cs,idl,java,php,datascript
 
 
 " Source the user-specified syntax highlighting file
-if exists("mysyntaxfile") && filereadable(expand(mysyntaxfile))
-  execute "source " . mysyntaxfile
+if exists("mysyntaxfile")
+  let s:fname = expand(mysyntaxfile)
+  if filereadable(s:fname)
+    execute "source " . fnameescape(s:fname)
+  endif
 endif
 
 " Restore 'cpoptions'