Function lua_pushthread

lib/lua/src/lapi.c:624–630

LUA_API int lua_pushthread (lua_State *L) {
  lua_lock(L);
  setthvalue(L, s2v(L->top.p), L);
  api_incr_top(L);
  lua_unlock(L);
  return (G(L)->mainthread == L);
}