list' should be an extern'd char **', not a local `char *' which we

never set.  Ideally, we'd get the extern from tutor.h, but that
defines a number of other variables that conflict with ours.

This fixes a segmentation fault when trying to return to the main menu.

PR:		30172

games/backgammon/teachgammon/ttext2.c

@@ -41,7 +41,8 @@ static const char rcsid[] =
 
 #include "back.h"
 
-char *prompt, *list, *opts;
+extern const char *const list[];
+char *prompt, *opts;
 
 const char	*const doubl[] = {
     "\nDoubling:",