[ECOS] File access under linux synthetic target

[Andrew Over <s341603 at student dot uq dot edu dot au>]

Hi.

For various reasons, I'd like to be able to get at native files from
under the linux synthetic target.  I also need fseek and ftell.
Before I started coding, I thought it might be an idea to get others
opinions on the "best" way to do this.

Out of interest, has anyone done any work along these lines?

My current plan is to hack the cyg_devio_table_t to include a few
extra functions (open, close, seek), fix the stdio code to use the new 
callbacks, add a new device which implements native file access under
the synthetic target, and hope not to break anything in the process :)

Suggestions welcome :)

Cheers,
--Andrew