It takes a long time to compile Mozilla. I suppose that the 250MB source tree ought to give you a hint... I'm not sure how long it took, exactly (I went to bed), but on my 2.0GHz AMD Linux box (512MB RAM, plenty of storage, yadda, yadda) it took half an hour at the very minimum.
And, of course, it didn't work.
So, I just gave up and created a program that converts iso-2022-jp to HTML. It's not a perfect solution, given the fact that (a) it doesn't work in titles, (b) I have to write the post in Emacs then convert the file to HTML, and (c) every single character is a escape sequence. Oh well.
So, here I am, deleting all the useless Mozilla sources -- no point in upgrading if all the old stuff works fine. Feh.
Update: Never mind... It does work in titles (I guess because it's not a tag).
All this work, and it turns out I just had a couple of locale settings wrong.
On the good side, now I know the specifications for EUC and iso-2022-jp.