mdocml is a suite of tools compiling mdoc, the roff macro package of choice for
BSD manual pages, and man, the predominant historical package for UNIX manuals.
It is small, ISO C, ISC-licensed, and quite fast.

The tool set features mandoc, based on the libmandoc validating compiler, to
format output for UNIX terminals (with support for wide-character locales),
XHTML, HTML, PostScript, and PDF. It also includes preconv, for recoding
multibyte manuals; demandoc, for emitting only text parts of manuals; mandocdb,
for indexing manuals; and apropos, whatis, and man.cgi (via catman) for
semantic search of manual content.

There is an environment variable called REPLACE_MAN, that if set to a non-empty
string, will instruct the slackbuild script to replace the stock man package
(you should remove(pkg) it first, though).

After installing, make sure to (re)create the mandoc specific "whatis"
database(s) in your manpath(s), eg.:
# mandocdb /usr/man /usr/local/man
... or, if you've chosen to replace man, then:
# makewhatis /usr/man /usr/local/man