rawlen usage makes extension incompatible with LuaJIT-based implementations

[tsafin]

Tarantool as database, and application server uses LuaJIT for Lua support in appserver. By default it's compiled without LUAJIT_ENABLE_LUA52COMPAT defined thus rawlen is inaccessible in majority of a cases.

This is kinda worked around in a code via

// Lua 5.2+ versions
declare function rawlen<T extends AnyTable>(this: void, v: T | string): number;
...
export const luaRawLen = rawlen ?? function<T extends AnyTable>(v: T | string): number {
}

which is translated to Lua as

____exports.luaRawLen = rawlen or (function(v)
...
end)

But this is not working either if strict mode enabled (which is default for Debug build here).

P.S.
It should probably wrapped in rawget.