tools: Use platform abstraction for I/O.
* tools/gpgconf-comp.c (retrieve_options_from_file): Use a gpgrt_stream_t for 'list_file'. Adapt accordingly. (copy_file): Likewise for 'src' and 'dst'. (change_options_file): Likewise for 'src_file' and 'dest_file'. (change_options_program): Likewise for 'src_file' and 'dest_file'. (gc_process_gpgconf_conf): Likewise for 'config'.
Werner asked me to make gpgconf use the platform abstractions that
were introduced after gpgconf's inception.
- Signed-off-by: Justus Winter <justus@g10code.com>