Bash-5.2 patch 1: fix crash with unset arrays in arithmetic contexts

patchlevel.h

@@ -25,6 +25,6 @@
    regexp `^#define[ 	]*PATCHLEVEL', since that's what support/mkversion.sh
    looks for to find the patch level (for the sccs version string). */
 
-#define PATCHLEVEL 0
+#define PATCHLEVEL 1
 
 #endif /* _PATCHLEVEL_H_ */

subst.c

@@ -10857,7 +10857,7 @@ expand_array_subscript (string, sindex, quoted, flags)
   exp = substring (string, si+1, ni);
   t = expand_subscript_string (exp, quoted & ~(Q_ARITH|Q_DOUBLE_QUOTES));
   free (exp);
-  exp = sh_backslash_quote (t, abstab, 0);
+  exp = t ? sh_backslash_quote (t, abstab, 0) : savestring ("");
   free (t);
 
   slen = STRLEN (exp);