A pointer to a DATASET structure if all went well, NULL if an error
occured.
FUNCTION
This routine uses the find_full_fname function to expand the filename.
If the file is not found, the function returns NULL. If it is, a pipe
is opened to the zcat shell command and the fscanf_dataset function is called.
NOTE
This function is used by the load_dataset function.
The zcat command must be available in the user's search path. Reading
compressed files does not work under Turbo-C / MS-DOS, since this combination
does not support pipes.
There may be a problem with portability using too long filenames. When
a network is written in compressed form, .Z is added to the filename.
If this filename already contains an extension, the file will not be
properly named under MS-DOS.
