feat: 适配 Lua 5.1.5 (lua_5.1.5 分支)

- lib/lua 替换为 Lua 5.1.5 官方源码; CMakeLists 删除 5.1 不存在的
  lcorolib.c/lctype.c/lutf8lib.c/lbitlib.c
- 补充 lua.hpp C++ 包装头(5.1 官方不提供, 保持桥接 include 路径不变)
- LUA_OK 兼容宏: 5.1 无此定义(成功返回值为 0)
- luaL_tolstring 兼容: 5.1 无此 API, l_print 改用 lua_tostring +
  lua_typename 兜底(#if LUA_VERSION_NUM >= 502 条件编译, 弹栈逻辑同步分支)
- luaL_setfuncs 兼容: 5.1 无此 API, push_tty_file 改手动循环注册
- I/O 重定向沿用 Registry 方案(自 5.2.4 分支同步), typed interop
  版本自适应断言同步
- 验证: GTest 44/44 通过

lib/lua/lzio.c

@@ -1,17 +1,15 @@
 /*
-** $Id: lzio.c $
-** Buffered streams
+** $Id: lzio.c,v 1.31.1.1 2007/12/27 13:02:25 roberto Exp $
+** a generic input stream interface
 ** See Copyright Notice in lua.h
 */
 
-#define lzio_c
-#define LUA_CORE
-
-#include "lprefix.h"
-
 
 #include <string.h>
 
+#define lzio_c
+#define LUA_CORE
+
 #include "lua.h"
 
 #include "llimits.h"
@@ -27,11 +25,23 @@ int luaZ_fill (ZIO *z) {
   lua_unlock(L);
   buff = z->reader(L, z->data, &size);
   lua_lock(L);
-  if (buff == NULL || size == 0)
-    return EOZ;
-  z->n = size - 1;  /* discount char being returned */
+  if (buff == NULL || size == 0) return EOZ;
+  z->n = size - 1;
   z->p = buff;
-  return cast_uchar(*(z->p++));
+  return char2int(*(z->p++));
+}
+
+
+int luaZ_lookahead (ZIO *z) {
+  if (z->n == 0) {
+    if (luaZ_fill(z) == EOZ)
+      return EOZ;
+    else {
+      z->n++;  /* luaZ_fill removed first byte; put back it */
+      z->p--;
+    }
+  }
+  return char2int(*z->p);
 }
 
 
@@ -48,14 +58,8 @@ void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
 size_t luaZ_read (ZIO *z, void *b, size_t n) {
   while (n) {
     size_t m;
-    if (z->n == 0) {  /* no bytes in buffer? */
-      if (luaZ_fill(z) == EOZ)  /* try to read more */
-        return n;  /* no more input; return number of missing bytes */
-      else {
-        z->n++;  /* luaZ_fill consumed first byte; put it back */
-        z->p--;
-      }
-    }
+    if (luaZ_lookahead(z) == EOZ)
+      return n;  /* return number of missing bytes */
     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
     memcpy(b, z->p, m);
     z->n -= m;
@@ -66,3 +70,13 @@ size_t luaZ_read (ZIO *z, void *b, size_t n) {
   return 0;
 }
 
+/* ------------------------------------------------------------------------ */
+char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
+  if (n > buff->buffsize) {
+    if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
+    luaZ_resizebuffer(L, buff, n);
+  }
+  return buff->buffer;
+}
+
+