insert Lua version

Instead of the hardcoded value that's in this right at the moment,
the intention is to get the Lua version information directly from
Lua itself for the insertion. For now, this will have to do.

src/mdlib.c

@@ -637,7 +637,7 @@ build_options()
     {
         static const char *lua_info[] = {
  "", "NetHack 3.7.* uses the 'Lua' interpreter to process some data:", "",
- "    About Lua: Copyright (c) 1994-2017 Lua.org, PUC-Rio.", "",
+ "    About Lua:LUAVERSION:: Copyright (c) 1994-2017 Lua.org, PUC-Rio.", "",
  /*        1         2         3         4         5         6         7
   1234567890123456789012345678901234567890123456789012345678901234567890123456
   */

src/version.c

@@ -303,6 +303,7 @@ static struct rt_opt {
     const char *token, *value;
 } rt_opts[] = {
     { ":PATMATCH:", regex_id },
+    { ":LUAVERSION:", " 5.3.5"}, /* plan is to get this directly from Lua */
 };
 
 /*