I noticed that the print/texinfo port (7.1) renames the executables to
'gtexinfo', 'gtexi2any' and so on, to avoid conflict with the older
version 4.2 of texinfo in Base.

A post-install target is also used to prefix the .info files installed
in /usr/local/info with 'g':

   cd ${PREFIX}/info && for i in *.info*; do mv $$i g$$i; done

However, after this renaming, 'info gtexinfo' and 'ginfo gtexinfo'
(etc...) do not work, because the metadata in the source .texi files
still refers to the original executable names. This metadata is put into
/usr/local/info/dir, and the renamed files are not found.

Removing the Makefile post-install line to rename the .info files
restores expected operation, that is:

'info texinfo' gives the info file for Texinfo 4.2 in base
'info gtexinfo' gives the info file for Texinfo 7.1 from ports.
'info 'gtexi2any' gives a manpage, but there is an up-to-date section
in 'info gtexinfo' that covers it, which is how I think it's supposed
to be.
'info ginfo-stnd' works OK.

I have tested the tweak on 7.8 Release/amd64.
 
-- 
Chris Billington