patch 8.0.0971: 'winptydll' missing from :options

Problem:    'winptydll' missing from :options.
Solution:   Add the entry.

runtime/optwin.vim

@@ -1,7 +1,7 @@
 " These commands create the option window.
 "
 " Maintainer:	Bram Moolenaar <Bram@vim.org>
-" Last Change:	2017 Aug 11
+" Last Change:	2017 Aug 19
 
 " If there already is an option window, jump to that one.
 let buf = bufnr('option-window')
@@ -510,6 +510,10 @@ if has("terminal")
   call append("$", "termkey\tkey that precedes Vim commands in a terminal window")
   call append("$", "\t(local to window)")
   call <SID>OptionL("tk")
+  if exists("&winptydll")
+    call append("$", "winptydll\tname of the winpty dynamic library")
+    call <SID>OptionG("winptydll", &winptydll)
+  endif
 endif
 
 

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    971,
 /**/
     970,
 /**/