Just lately I reinstalled my Gentoo server and when it came to putting Handbrake back on the system Portage began complaining that it was failing to emerge automake version 1.11.6. After checking the system I could see that I already had version 1.15 but that should not be causing the issue as the two should slot next to each other. After much messing around I finally have a work around to get this working, with help from the Gentoo forums.
If we remove Texinfo and emerge Handbrake then the task completes successfully and then we can add Texinfo back onto the system. You can read more about Texinfo here
If you use this one liner you can remove texinfo, install handbrake and then reinstall texinfo
emerge -C sys-apps/texinfo && emerge -jv handbrake && emerge -jv sys-apps/texinfo