Let's have strict error checking as part of the build process, in order to
catch any issue earlier rather than later. As Phil found out there is a
--error-limit flag to makeinfo and texi2html whose default values are
respectively 100 and 1000. That's a 1000 errors until texi2html decides to
stop and go no further. It is proposed to run makeinfo and texi2html with
--error-limit=0.