Obsolete nosetarch option
Created by: holymonson
setarch is mainly used for building i686 packages on x86_64, while it disturbs building ARM packages on x86_64, so the nosetarch option (-s) was introduced. But there is a better way that we could always precheck the setarch support list, and do it only when available.
This could fix the partial implement of setarch refered on #41 .
Close #41