Large GRIB1
GRIB1 uses a weird hack (see eccodes src/grib_io.c
/* Large GRIBs */
) in which some bits of the length of the section4 header can sometimes be used to encode larger than 2**24-sized grib files.
This MR adds a parser for this hack to _split_file
, such that those messages can also be scanned by gribscan.