LUA_RIDX_GLOBALS
gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
const TValue *gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt);
lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS)
#define LUA_RIDX_LAST LUA_RIDX_GLOBALS