I have some old documents/manuals that were originally formatted with the mm macros. When I attempted to format them with the newer release groff 1.22.2 version of the m.tmac macros, m.tmac revision 2.53, there was a problem with the heading macros, namely
.H 3 "Title"
resulted in Following text... overwriting the entire heading line, even when .nr Hs 2 and .nr Hb 2. I.e. there is a problem when the text is to be on the same line as the heading number. Somehow a bug has crept into the 2.53 m.tmac macros.
I've looked at the m.tmac macros, rev. 2.53, and it seems like .nr hd*htype 0 should have handled the problem, but somehow it doesn't -- even though it did in the previous versions of groff that I have used.
I finally located an older version of the m.tmac macros, version 2.24, on-line. When I used the older version 2.24 m.tmac macros the document headings and following text formatted correctly.
Is there a newer version than m.tmac 2.53 that corrects the heading bug?