Re: BUG #16345: ts_headline does not find phrase matches correctly

In short then, I propose applying 0001-0006.  I'm not quite sure
if we should back-patch, or just be content to fix this in HEAD.
But there's definitely an argument that this has been broken since
we added phrase search (in 9.6) and deserves to be back-patched.

wparser_def.c: In function 'prsd_headline':
wparser_def.c:2530:2: warning: 'pose' may be used uninitialized in this function [-Wmaybe-uninitialized]
  mark_fragment(prs, highlightall, bestb, beste);
  ^
wparser_def.c:2384:6: note: 'pose' was declared here
  int   pose,