[feature request] Compile bitwise operators into Lua BitOp functions calls

[SkyyySi]

For Lua versions below 5.3, bitwise operators aren't supported. However, their behavior can be substituted using the Lua BitOp library. This library is also included by default with LuaJIT. My suggestion would be to add a boolean argument to the compiler, perhaps a --use-bit-lib (which is what Fennel also uses). In practice, it could compile the code:

bit_or = (x, y) ->
    x | y

into this:

_bitop_0 = require("bit")
local bit_or
bit_or = function(x, y)
    return _bitop_0.bor(x, y)
end

[SkyyySi]

Additionally, the floor division operator x // y could be compiled to math.floor(x / y).

[SkyyySi]

An alternative might be to allow choosing the bit library, as Lua 5.2 includes the "bit32" library by default.