with the last stable version 4.6.2, the make on gnuplot.texi fails with the following error :
./gnuplot.texi:17653: raising the section level of @subsubsection which is too low
the error is in the @section "complete list of terminals" being followed by a @subsubsection (without a @subsection between).
The error has been seen on Arch linux x64 (GNU make version 3.82).
a patch is provided to change every faulty @subsubsection to @subsection but I don't know if it is what the author would have done.