Log Message:
Fix assorted build problems. Should close PR 42081. While here, add at
least minimal comments to all patches and tidy up some (but by no
means all) pkglint.

I have no idea if this works. It spews warnings about "packed", which
lead me to suspect it may not run correctly, but I don't have the
facilities to test it. It does, however, now build ok on LP64 and if
someone can test it may be reasonable to remove the restriction on that.