exec, passthru, system
exec, passthru, system

fixes https://github.com/peachpiecompiler/peachpie/issues/448

peachpiecompiler/peachpie,peachpiecompiler/peachpie,iolevel/peachpie-concept,iolevel/peachpie,peachpiecompiler/peachpie,iolevel/peachpie,iolevel/peachpie,iolevel/peachpie-concept,iolevel/peachpie-concept