makeinfo is part of the texinfo distribution.
Get texinfo-*.tar.gz.

However, all GNU distributions should come with prebuilt info files,
thus makeinfo should not be needed.

Unfortunately, the gcc-2.7.2.2 distribution was made incorrectly, and
its info files are out of date.  You can avoid having to get and compile
makeinfo to install gcc by doing touch *.info* before make install, or
creating a makeinfo that is a link to /bin/true.  Finally, the Info files
are installed last, so you're not missing anything if you let it fail.

In Cygnus distributions (notably gdb and binutils), often info files are
not included.  For some reason they do not consider this a bug.  Thus
you must have makeinfo to run `make install-info'.

Otherwise, if makeinfo is being called by make install, perhaps you
removed the .info files (for example, by typing make realclean or make
maintainer-clean), or accidentally or purposefully modifying the Texinfo
sources.  In those cases, reretrieving the distribution will get them
back. Otherwise, it's a bug in the distribution, and you should report
it as such.