Bug#982705: openssh: FTBFS: sha2.h:57:16: error: redefinition of ‘struct _SHA2_CTX’

On Sun, Feb 14, 2021 at 08:32:58AM +0100, Andreas Henriksson wrote:
> Hello,
> 
> On Sat, Feb 13, 2021 at 06:04:32PM +0100, Lucas Nussbaum wrote:
> > Source: openssh
> > Version: 1:8.4p1-3
> > Severity: serious
> > Justification: FTBFS on amd64
[...]
> (Which in turn makes me wonder if something changed on the libmd side?)

So looked around a bit more here....

Apparently this is the reason libmd-dev is installed:

openssh b-d libedit-dev
libedit-dev dep libbsd-dev
libbsd-dev dep libmd-dev

Both libmd-dev and libbsd-dev seems to have had recent changes.

>From libbsd (0.11.1-1) changelog:
```
    - Switch from embedded hashing function implementations to use libmd.
      Add libmd-dev to Build-Depends and libbsd-dev Depends.
```

I have not yet looked up what the configure results where for the
last successful openssh build, but I suspect that the situation back
then was that SHA256Update et.al. where not found and the openssh compat
sha2.h was used, but this was not a problem because libmd-dev (which
provides /usr/lib/sha2.h) was not pulled in back then either...

Simply introducing an opennsh `Build-Conflicts: libmd-dev` will not work
now that we have a dependency chain which will pull it in via libedit-dev.

I suspect the way out of this is to simply improve the openssh configure
now...

Regards,
Andreas Henriksson