I think I know why the installed maxima can't find its info files.
The maxima script doesn't set MAXIMA_PREFIX so set-pathnames
eventually ends up setting *maxima-infodir* to be the same as
*autoconf-infodir*, but that is just the string "". Thus, maxima
doesn't can't find the info files.
Since I don't quite understand how this is all supposed to interact,
I'm not sure what the right answer should be. Possible solutions:
1. Have maxima set MAXIMA_PREFIX to be $prefix.
2. Make sure the autoconf variables in autoconf-variables.lisp have
something other than the empty string.
I think (2) is the right answer.
Ray