This is done by make, in the 'docs' target, which is now part of the
normal build process.
Unfortunately, not all the games include troff sources. Getting decent
HTML output from groff is still a difficult process which will not be
attempted at this time. There are a few bugs in the 'install' and
'uninstall' rules.
Not to mention that the documentation is sometimes inaccurate.
A custom autoconf macro searched for the curses library, and provided an
option to use ncurses instead of a (presumably deficient) curses
implementation. Unfortunately, some of the Makefiles ignored the
search's results.
Now that this is fixed, building against pdcurses should be easier too.
Some .o files need to be rebuilt if config.h changes. Adding it to the
list of headers may still fail to solve the problem, because some of
the Makefiles use implicit rules or do not list dependencies properly.