Hi Peter,
I reckon that is because those builds run on Ubuntu Precise, which has
only makeinfo version 4.13 I can't help but mention that 4.13 was released in 2008. I can easily understand plenty of users still using it, but as a developer, you could just install the current texinfo yourself, instead of living with what the distro decides to give you (or complicating scripts with conditionals). It's not like wget && tar && configure && make is a time-consuming task ... -k
