Suggest URLs for updated setup based on build architecture
Suggest URLs for updated setup based on build architecture, rather than
on that specified with '--arch'.
(Or maybe we should just point at cygwin.com/install.html? Since the URL
isn't clickable due to :reasons:)
Also: reword messages indicating setup should be updated for clarity,
don't mention the internal detail of an "ini file".
Future work: These messages (along with other errors coming from the ini
file parser), should be localizable.