Fix compilation of the --with-wide-int configuration

* src/alloc.c (mark_maybe_pointer): Fix a recent change for
WIDE_EMACS_INT builds.  (Bug#49261)

src/alloc.c

@@ -4764,7 +4764,11 @@ mark_maybe_pointer (void *p, bool symbol_only)
 	 from Emacs source code, it can occur in some cases.  To fix
 	 this problem, the pdumper code should grok non-initial
 	 addresses, as the non-pdumper code does.  */
+#ifdef WIDE_EMACS_INT
+      uintptr_t mask = ~((uintptr_t) 0);
+#else
       uintptr_t mask = VALMASK;
+#endif
       void *po = (void *) ((uintptr_t) p & mask);
       char *cp = p;
       char *cpo = po;