Take two arches and return True if it is possible that they can be installed together with the same nevr. Ex: arch1=i386 and arch2=i686 then it will return False. arch1=i386 and arch2=x86_64 will return True. It does not determine whether or not the arches make any sense. Just whether they could possibly install w/o conflict
returns true if arch is a multilib arch, false if not
return the best arch from the list for myarch if - myarch is not given, then return the best arch from the list for the canonArch.
returns ‘base’ arch for myarch, if specified, or canonArch if not. base arch is the arch before noarch in the arches dict if myarch is not a key in the multilibArches.