Hi Michal, In the Makefile, wouldn't it be easier to use .dvi files as targets, instead of .4ht files? I don't have deep understanding of Make, so maybe it has some advantage.
I made the .4ht files be the targets not for any technical reason, but for the sake of self-documentation for human consumption. That is, when I was first looking at the mass of several thousand tex4ht files, my basic question was which were the original source files and which were the derived (and where were they derived from). It was (and is) not at all obvious. So when I was constructing the Makefile, I did it one file at a time, trying to list the derived files for each. This is why, in our changes, I've tried hard to go through the pain of inserting "this file foo was created from this other bar on <date>" into the derived files, and also mark the original source files. I don't doubt I got some things wrong, and some are obviously incomplete (e.g., as you know, tex4ht-4ht.tex creates hundreds of derived files -- far from ideal if you ask me, but anyway). To me, the fact that running the "literate" .tex files through tex results in a DVI for "documentation" (often of minimal value, it seems to me) is much less important than the runtime files that get created. So it never occurred to me to make the dvi files be the primary targets. For true completeness, it is certainly true that dvi files should *also* be targets ... Hope this helps explain why I did what I did. If you see possible improvements to make, by all means let me know. Thanks for all your work. Karl