strings: revert caching of hash value.

Research indicates that this is something useful in
languages that abuse strings for implementing symbols.
We have interned symbols.

* lib.h (struct string): Remove hash member.

* lib.c (string_own, string, string_utf8, mkustring,
string_extend, replace_str, chr_str_set): Remove
all initializations and updates of the removed
hash member.

* hash.c (equal_hash): Do not cache string hash value.

1 files changed, 1 insertions, 3 deletions

diff --git a/lib.h b/lib.h
index 48320174..34f00c09 100644
--- a/lib.h
+++ b/lib.h
@@ -154,9 +154,7 @@ struct string {
   obj_common;
   wchar_t *str;
   val len;
-#if HAVE_MALLOC_USABLE_SIZE
-  ucnum hash;
-#else
+#if !HAVE_MALLOC_USABLE_SIZE
   cnum alloc;
 #endif
 };