I have installed autoconf-2.69 and 2.13 versions, all include own book versions.
Book version from 2.69 includes section "Portable C and C++", right after "Portable Make" and before "Manual Configuration". All sections, begining with "Portable C and C++" are unavailable for info reader from texinfo, which gives error: "No such file or directory". It is impossible even to get past this margin via search. E.g., if i search for AC_ARG_ENABLE (trying get to Site Configuration), it says "Cannot find node '(autoconf-2)VPATH and Make".
However, in info autoconf-2.1 there is no problems entering "Manual Configuration" and further.
But yet, other info readers (tried emacs, pinfo, tkinfo) have no mentioned problem with autoconf-2.69 too - actually i use tkinfo.
I can't understand, whose is that bug: invalid section in autoconf-2.69 book or error in texinfo reader.
Updating texinfo to 6.4 or 6.5 doesn't fix problem.
Though 6.5 item from NEWS mentions:
"another bug which could make nodes inaccessible in long "split" info files"
probably it is not about this bug.
...this is a bit misfiled
The problem has nothing to do with texinfo and just about everything with toolchain-autoconf eclass.
That old hack to prevent dependency loop by using neither makeinfo nor any of autotools, just sed, seems to fail once the slot number is 2.69.
I'm not sure how exactly info viewer works, but after series of test my guess is that after adding that much text to the file, some of the offsets are off by by too much for things to still work.
Unfortunatelly, short of rebuilding the page with makeinfo, I see no simple solution.