layer, which led to lots of problems; make it force read files as utf-8.
Closes: #373203
* writefile() likewise needs to use the utf8 output layer.
* Remove the -CSD from ikiwiki's hashbang since it's useless to have it
there.
* Revert some of the decode_utf8 changes in CGI.pm that seem unnecessary
given the readfile fix.
* Add utf-8 testcases for readfile and htmlize.
* When inlining a page in another one, links from the inlined page are now
expanded the same as they are when rendering the inlined page as a
standalone page. So rather than being expanded from the POV of the
inlining page, they are expanded from the POV of the inlined page.
For example, a link from blog/foo to "bar" will now link to blog/bar
if it exists. Previously this needed to be a link explicitly to
"blog/bar"; such links will also continue to work.
(This was slightly complex to do as the link still has to be constructed
relative to the inlining page.)
* Add a html validity check to the test suite, using the wdg-html-validator,
if available.
* Make the html valid when there is nothing in the actions list by adding an
empty <li> to the end of it.
* Reordered some function call parameters for consistency.