GNU for VMS gnulib_assist

GNV Provides a Framework for Porting Open Source Software to OpenVMS

Brought to you by: billpedersen, hp-gnv-devlp, is014, johnreagan, and 2 others

Convert more routines to use vms_string

Updated vms_rms_parse, vms_dir_to_did routines to use vms_string
structures instead of null terminated strings.

Signed-off-by: John Malmberg <wb8tyw@...>

Authored by: John Malmberg 2019-06-21

changed	vms/test_vms_dir_to_did.c
changed	vms/test_vms_name_to_fid_device.c
changed	vms/vms_dir_to_did.c
changed	vms/vms_filenames.h
changed	vms/vms_gnulib_assist.md
changed	vms/vms_realname.c
changed	vms/vms_rms_parse.c