Language-aware search

Modified title.

Very straightforward. Note that this doesn't provide and method for setting search preferences, you have to set the language every search. This is consistent with the other advanced search features.

It does not make much sense to use checkboxes for the language selection. I would rather see a select box here (a search term is rarely the same across different languages). Otherwise, the patch looks good.

Oh, and as a next step, we will also need a language-specific steemer and user-language aware search (but that's for another feature request).

select or radios? Which do people think are better?

Actually, I disagree. If Drupal.org were a mishmash of languages, I'd still search for Drupal in de and en.

Would you really search the *same exact word* in both English and German? Even if it could, as a corner case, make sense (for instance for family names or names of organizations), I'm not sure it would be really useful.

This one makes it a select. The side effect is that you can only search for one language, even if you use a syntax like language:en,ar,de, it won't work. The select now contains an option "All" which is the default.

Well, especially with German, there are lots of words which that language share with English, at least in the tech world I know. I'd support selecting multiple languages. Why make it impossible?

I should be able to work it out so that we have a select widget, but the extraction supports multiple values (so a url with language:en,de,ar would work). That way someone could come along and form_alter the widget if they need. Will do this tomorrow unless someone else takes a stab.

This one leaves the select widget but allows for language:en,de,jp,ar syntax.

I might want to search for the word 'Drupal' in English, Dutch and French, but not in Chinese or Japanese. A lot of words, and names in particular, are language independent. I think this is a nice little improvement. (Would even be better if it came with a simpletest.)

I've tested this some more and committed it to CVS HEAD. Thanks.