To get a list of files in the current working directory.
SUBROUTINE GET_FILES@(WILDCARD, FILES, MAXFILES, NFILES,
CHARACTER (LEN=*) WILDCARD, FILES(MAXFILES)
INTEGER (KIND=2) MAXFILES, NFILES, ERROR_CODE
Returns a list of all the files in the current working directory which can be
matched by WILDCARD.
Returns error code ERROR_CODE as ERANGE if FILES is not big enough, but the
entries which are stored in FILES will be valid.