Explicitly specify that OCTAVE_VERSION is a builtin. Otherwise the call to
“exists” will look for a file, among other things, which takes a lot of time.
It is now supported by the MATLAB editor (as of R2022a).
The old ASCII notation is left in some files that we copy as-is from other
sources (e.g. in the contrib/ and m4/ subdirectories).
The particles submodule is not updated at this point, because it is in an
inconsistent state.
[skip ci]