Bring Lua to 5.4.6. (#1214)

This essentially re-does the work of #875 on top of master.

This is what I did to check that Cosmo's Lua extensions still worked:

```
$ build/bootstrap/make MODE=aarch64 o/aarch64/third_party/lua/lua
$ ape o/aarch64/third_party/lua/lua
>: 10
10
>: 010
8
>: 0b10
2
>: string.byte("\e")
27
>: "Hello, %s" % {"world"}
Hello, world
>: "*" * 3
***
```

`luaL_traceback2` was used to show the stack trace with parameter
values; it's used in `LuaCallWithTrace`, which is used in Redbean to run
Lua code. You should be able to see the extended stack trace by running
something like this: `redbean -e "function a(b)c()end a(2)"` (with
"params" indicating the extended stack trace):

```
stack traceback:
 [string "function a(b)c()end a(2)"]:1: in function 'a', params: b = 2;
 [string "function a(b)c()end a(2)"]:1: in main chunk
```
@pkulchenko confirmed that I get the expected result with the updated
code.

This is what I did to check that Lua itself still worked:

```
$ cd third_party/lua/test/
$ ape ../../../o/aarch64/third_party/lua/lua all.lua
```

There's one test failure, in `files.lua`:

```
***** FILE 'files.lua'*****
testing i/o
../../../o/aarch64/third_party/lua/lua: files.lua:84: assertion failed!
stack traceback:
[C]: in function 'assert'
files.lua:84: in main chunk
(...tail calls...)
all.lua:195: in main chunk
[C]: in ?
.>>> closing state <<<
```

That isn't a result of these changes; the same test is failing in
master.

The failure is here:

```lua
if not _port then   -- invalid seek
  local status, msg, code = io.stdin:seek("set", 1000)
  assert(not status and type(msg) == "string" and type(code) == "number")
end
```

The test expects a seek to offset 1,000 on stdin to fail — but it
doesn't. `status` ends up being the new offset rather than `nil`.

If I comment out that one test, the remaining tests succeed.

third_party/lua/ltable.c

@@ -3,7 +3,7 @@
 ╚──────────────────────────────────────────────────────────────────────────────╝
 │                                                                              │
 │  Lua                                                                         │
-│  Copyright © 2004-2021 Lua.org, PUC-Rio.                                     │
+│  Copyright © 2004-2023 Lua.org, PUC-Rio.                                     │
 │                                                                              │
 │  Permission is hereby granted, free of charge, to any person obtaining       │
 │  a copy of this software and associated documentation files (the             │
@@ -27,6 +27,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #define ltable_c
 #define LUA_CORE
+
 #include "third_party/lua/ldebug.h"
 #include "third_party/lua/ldo.h"
 #include "third_party/lua/lgc.h"
@@ -100,8 +101,6 @@ __static_yoink("lua_notice");
 #define hashstr(t,str)		hashpow2(t, (str)->hash)
 #define hashboolean(t,p)	hashpow2(t, p)
 
-#define hashint(t,i)		hashpow2(t, i)
-
 
 #define hashpointer(t,p)	hashmod(t, point2uint(p))
 
@@ -117,6 +116,20 @@ static const Node dummynode_ = {
 static const TValue absentkey = {ABSTKEYCONSTANT};
 
 
+/*
+** Hash for integers. To allow a good hash, use the remainder operator
+** ('%'). If integer fits as a non-negative int, compute an int
+** remainder, which is faster. Otherwise, use an unsigned-integer
+** remainder, which uses all bits and ensures a non-negative result.
+*/
+static Node *hashint (const Table *t, lua_Integer i) {
+  lua_Unsigned ui = l_castS2U(i);
+  if (ui <= cast_uint(INT_MAX))
+    return hashmod(t, cast_int(ui));
+  else
+    return hashmod(t, ui);
+}
+
 
 /*
 ** Hash for floating-point numbers.
@@ -150,26 +163,24 @@ static int l_hashfloat (lua_Number n) {
 
 /*
 ** returns the 'main' position of an element in a table (that is,
-** the index of its hash value). The key comes broken (tag in 'ktt'
-** and value in 'vkl') so that we can call it on keys inserted into
-** nodes.
+** the index of its hash value).
 */
-static Node *mainposition (const Table *t, int ktt, const Value *kvl) {
-  switch (withvariant(ktt)) {
+static Node *mainpositionTV (const Table *t, const TValue *key) {
+  switch (ttypetag(key)) {
     case LUA_VNUMINT: {
-      lua_Integer key = ivalueraw(*kvl);
-      return hashint(t, key);
+      lua_Integer i = ivalue(key);
+      return hashint(t, i);
     }
     case LUA_VNUMFLT: {
-      lua_Number n = fltvalueraw(*kvl);
+      lua_Number n = fltvalue(key);
       return hashmod(t, l_hashfloat(n));
     }
     case LUA_VSHRSTR: {
-      TString *ts = tsvalueraw(*kvl);
+      TString *ts = tsvalue(key);
       return hashstr(t, ts);
     }
     case LUA_VLNGSTR: {
-      TString *ts = tsvalueraw(*kvl);
+      TString *ts = tsvalue(key);
       return hashpow2(t, luaS_hashlongstr(ts));
     }
     case LUA_VFALSE:
@@ -177,26 +188,25 @@ static Node *mainposition (const Table *t, int ktt, const Value *kvl) {
     case LUA_VTRUE:
       return hashboolean(t, 1);
     case LUA_VLIGHTUSERDATA: {
-      void *p = pvalueraw(*kvl);
+      void *p = pvalue(key);
       return hashpointer(t, p);
     }
     case LUA_VLCF: {
-      lua_CFunction f = fvalueraw(*kvl);
+      lua_CFunction f = fvalue(key);
       return hashpointer(t, f);
     }
     default: {
-      GCObject *o = gcvalueraw(*kvl);
+      GCObject *o = gcvalue(key);
       return hashpointer(t, o);
     }
   }
 }
 
 
-/*
-** Returns the main position of an element given as a 'TValue'
-*/
-static Node *mainpositionTV (const Table *t, const TValue *key) {
-  return mainposition(t, rawtt(key), valraw(key));
+l_sinline Node *mainpositionfromnode (const Table *t, Node *nd) {
+  TValue key;
+  getnodekey(cast(lua_State *, NULL), &key, nd);
+  return mainpositionTV(t, &key);
 }
 
 
@@ -264,9 +274,11 @@ LUAI_FUNC unsigned int luaH_realasize (const Table *t) {
     size |= (size >> 2);
     size |= (size >> 4);
     size |= (size >> 8);
+#if (UINT_MAX >> 14) > 3  /* unsigned int has more than 16 bits */
     size |= (size >> 16);
 #if (UINT_MAX >> 30) > 3
     size |= (size >> 32);  /* unsigned int has more than 32 bits */
+#endif
 #endif
     size++;
     lua_assert(ispow2(size) && size/2 < t->alimit && t->alimit < size);
@@ -495,7 +507,7 @@ static void setnodevector (lua_State *L, Table *t, unsigned int size) {
       luaG_runerror(L, "table overflow");
     size = twoto(lsize);
     t->node = luaM_newvector(L, size, Node);
-    for (i = 0; i < (int)size; i++) {
+    for (i = 0; i < cast_int(size); i++) {
       Node *n = gnode(t, i);
       gnext(n) = 0;
       setnilkey(n);
@@ -695,7 +707,7 @@ void luaH_newkey (lua_State *L, Table *t, const TValue *key, TValue *value) {
       return;
     }
     lua_assert(!isdummy(t));
-    othern = mainposition(t, keytt(mp), &keyval(mp));
+    othern = mainpositionfromnode(t, mp);
     if (othern != mp) {  /* is colliding node out of its main position? */
       /* yes; move colliding node into free position */
       while (othern + gnext(othern) != mp)  /* find previous */
@@ -982,6 +994,4 @@ Node *luaH_mainposition (const Table *t, const TValue *key) {
   return mainpositionTV(t, key);
 }
 
-int luaH_isdummy (const Table *t) { return isdummy(t); }
-
 #endif