unpacks_multiple_return_values: reduce allowed size to 2
unpacks_multiple_return_values: reduce allowed size to 2

This is a temporary solution to make viewport size roundtrip through Lua
scripts.

sunu/splash,Youwotma/splash,dwdm/splash,kod3r/splash,dwdm/splash,pawelmhm/splash,kmike/splash,pombredanne/splash,kmike/splash,pawelmhm/splash,pombredanne/splash,kod3r/splash,pawelmhm/splash,dwdm/splash,kod3r/splash,kmike/splash,Youwotma/splash,sunu/splash,sunu/splash,Youwotma/splash,pombredanne/splash