support mingw64, according to [Add partial support for building with MingW64 GCC 4.8-SEH.](https://github.com/LuaJIT/LuaJIT/commit/1a5fd521b830a8aa17c12d2e707d167722e8c7b1)
support mingw64, according to [Add partial support for building with MingW64 GCC 4.8-SEH.](https://github.com/LuaJIT/LuaJIT/commit/1a5fd521b830a8aa17c12d2e707d167722e8c7b1)

luvit/luv,zhaozg/luv,joerg-krause/luv,joerg-krause/luv,luvit/luv,zhaozg/luv