The libbu and libdm man pages were originally DocBook conversions of
files from elsewhere in the documentation.  They have since been
rewritten as proper man3 overview pages and are now built alongside the
other man3 pages.

libpc and libtermio have man3 overview pages here but are not currently
built as standalone libraries with their own CMake targets (libtermio is
header-only; libpc has no addlib target unless GECODE support is
enabled).  Their pages are therefore tracked but only built once an
associated library target exists.
