[patch] mark one instance of tun_fwd_ifnames as extern

[Damien Miller]

On Sat, 12 Jan 2019, Hanno Böck wrote:

> Hi,
> 
> The global variable tun_fwd_ifnames is used in both session.c and
> serverloop.c.
> 
> This means one of them has to be marked as extern. Most compilers will
> ignore such errors, but it's not correct. E.g. in gcc you can enable a
> stricter handling of global variables with -fno-common.
> 
> See attached patch, which will mark it as extern in sessions.c. (the
> other variables in that block are already marked extern, so it seems
> fitting.)

Committed and added -fno-common to my local build flags :)

-d