> CGI-generated pages should generate those links. This was the implementation of
> [[todo/want_to_avoid_ikiwiki_using_http_or_https_in_urls_to_allow_serving_both]].
>
+>> This wasn't actually the case if the schemes are different; but now
+>> IkiWiki will generate protocol-relative URLs if the CGI is https,
+>> the url is http and the hostname is the same (i.e. it assumes that the https
+>> equivalent of the url will also work). This is to prevent mixed-content
+>> issues, and partially addresses this todo item.
+>> --[[smcv]]
+>
> If your`$config{url}` and `$config{cgiurl}` have different hostnames (e.g.
> `url => "http://wiki.example.com", cgiurl => "http://cgi.example.com/ikiwiki.cgi"`)
> then you might still have this problem. In principle, IkiWiki could generate
> protocol-relative URLs in this situation, but it isn't clear to me how
> widely-supported those are.
>
+>> HTML5 says protocol-relative URLs work, and they seem to be widely
+>> supported in practice, so I've changed the rule to: if the url and cgiurl
+>> share a scheme (protocol) but differ only by hostname, use `//foo/bar`
+>> protocol-relative URLs. This partially addresses this todo.
+>> I'm still thinking about what the right thing is for more complicated
+>> situations: see [[todo/design for cross-linking between content and CGI]].
+>> --[[smcv]]
+>
> If you set both the `$config{url}` and `$config{cgiurl}` to https, but make
> the resulting HTML available over HTTP as well as HTTPS, that should work
> fine - accesses will be over http until the user either explicitly