[libgfortran,patch] Build libgfortran when dup() and access() are not available

[Tobias Burnus]

Salut François-Xavier,

FX Coudert wrote:
> This patch provides a fallback implementation of acces(), using
> open(), that covers the cases used in io/unix.c. For dup(), the
> graceful degradation is probably the best we can provide, and should
> only fail when closing pre-connected units. (But then, for embedded
> targets, I'd say: so be it.)
>
> Manually testeed on x86_64-linux, OK to commit?

OK - thanks for fixing embedded systems.

Tobias

PS: An alternative command to dup(fildes) is fcntl(fildes, F_DUPFD, 0);
one could think of using that if dup() is not available. However, as
fcntl F_DUPFD will then probably be not available, either, one should
presumably not worry.