Revert "allow readobjnam arg to be nonnull"

This reverts commit 10f29a9760.

include/decl.h

@@ -1156,7 +1156,6 @@ struct const_globals {
 extern const struct const_globals cg;
 
 extern struct obj hands_obj;
-extern char do_random_str;
 
 #endif /* DECL_H */
 

include/extern.h

@@ -2125,7 +2125,10 @@ extern char *bare_artifactname(struct obj *) NONNULLARG1;
    that leads to impossible(), preventing NONNULLARG1 */
 extern char *makeplural(const char *) NO_NONNULLS;
 extern char *makesingular(const char *) NO_NONNULLS;
-extern struct obj *readobjnam(char *, struct obj *) NONNULLARG1;
+/* readobjnam() allows a NULL to trigger code path for random; if it
+   and its caller were modifed to look for/provide a particular address
+   to use as a trigger instead, it could be declared NONNULLARG1 */
+extern struct obj *readobjnam(char *, struct obj *) NO_NONNULLS;
 extern int rnd_class(int, int);
 /* discover_object() passes NULL arg2 to Japanese_item_name(),
  * preventing NONNULLARG2 */

src/decl.c

@@ -1069,10 +1069,8 @@ decl_globals_init(void)
     gu.urace = urace_init_data;
 }
 
-/* fields in 'hands_obj' and contents of 'do_random_str' don't matter,
- * just their distinct addresses */
+/* fields in 'hands_obj' don't matter, just its distinct address */
 struct obj hands_obj = DUMMY;
-char do_random_str = '\0';
 
 /* gcc 12.2's static analyzer thinks that some fields of gc.context.victual
    are uninitialized when compiling 'bite(eat.c)' but that's impossible;

src/objnam.c

@@ -4576,7 +4576,7 @@ readobjnam_postparse3(struct _readobjnam_data *d)
 
 
 /*
- * Return something wished for.  Specifying &do_random_str for
+ * Return something wished for.  Specifying a null pointer for
  * the user request string results in a random object.  Otherwise,
  * if asking explicitly for "nothing" (or "nil") return no_wish;
  * if not an object return &hands_obj; if an error (no matching object),
@@ -4588,7 +4588,7 @@ readobjnam(char *bp, struct obj *no_wish)
     struct _readobjnam_data d;
 
     readobjnam_init(bp, &d);
-    if (bp == &do_random_str)
+    if (!bp)
         goto any;
 
     /* first, remove extra whitespace they may have typed */

src/zap.c

@@ -6024,7 +6024,7 @@ makewish(void)
         if (++tries < MAXWISHTRY)
             goto retry;
         pline1(thats_enough_tries);
-        otmp = readobjnam(&do_random_str, (struct obj *) 0);
+        otmp = readobjnam((char *) 0, (struct obj *) 0);
         if (!otmp)
             return; /* for safety; should never happen */
     } else if (otmp == &nothing) {