umegaya/ffiex — pull request #13 by umegaya (2014-06-10 05:40:04+00:00)
Title: fix bug that inter-state import of same symbol is possible but causes error.

``` lua
local s1, s2 = ffi.newstate(), ffi.newstate()

s1:copt { cc = "gcc" }
s2:copt { cc = "gcc" }

s1:import({"nanosleep"}):from [[
#include
#include
]]
s2:import({"kevent"}):from [[
#include
#include
#include
]] --[[ causes error attempt to redefine 'timespec' at line 25,
because previous ffiex cannot check the attempt to import same symbol over 2 state.
its basically blocked for same state, because of C style include guard.]]
```