tar: fix --exclude-vcs-ignores memory

The function frees the patterns' wordsplit structure without asking
add_exclude to reallocate the strings.  In many cases, this leads to
each file name in the directory being checked against the memory
location where it just got reallocated.
* src/exclist.c: Use EXCLUDE_ALLOC.
Copyright-paperwork-exempt: Yes

src/exclist.c

@@ -203,6 +203,7 @@ cvs_addfn (struct exclude *ex, char const *pattern, int options, void *data)
   struct wordsplit ws;
   size_t i;
 
+  options |= EXCLUDE_ALLOC;
   if (wordsplit (pattern, &ws,
 		 WRDSF_NOVAR | WRDSF_NOCMD | WRDSF_SQUEEZE_DELIMS))
     return;