[Lightning] jit_state _jit, re-entrancy

[Sandro Magi]

Section 2.4, Re-entrant usage of gnu lightning, states that
lightning's state is in a static global symbol "_jit". I'm not clear
on what the re-entrant use of "static to a function" means, but I
think this coincides with how I was planning to use lightning: by
passing a _jit parameter to all of my code generating functions. Since
Lightning is based purely on macro expansion, the expanded instruction
stream would reference the function's local _jit for its state, and
code generation is thus re-entrant, correct?

void code_add_instr(jit_state _jit, ...) {
   /* use jit_* functions which will reference the _jit local variable */
}

Sandro