[FFmpeg-devel] [PATCH] Fix build with LibreSSL

[Matt Oliver]

On 30 October 2016 at 17:57, Michael Forney <mforney at mforney.org> wrote:

> On 10/29/16, Matt Oliver <protogonoi at gmail.com> wrote:
> > This also seems a bit odd, why is libreSSL setting an openssl version
> > number of 1.1.0 or higher when it doesnt actually conform to the
> > corresponding openssl version. LibreSSl setting the openssl version
> number
> > to 2.0.0 seems to be problematic and causes problems not just for ffmpeg.
> > Of course theres not much we can do about that but perhaps an alternative
> > to Michaels suggestion would be to just add a single check near the top
> of
> > the file that checks for libressl and then redefines the openssl version
> to
> > the api libressl actually supports. i.e.
> >
> > #ifdef LIBRESSL_VERSION_NUMBER
> > #undef OPENSSL_VERSION_NUMBER
> > #define OPENSSL_VERSION_NUMBER 0x1000107fL
> > #endif
> >
> > This I believe is what some other projects have done to avoid this issue
> > and is rather simple to add and prevents further clutter in our
> configure.
> > I dont have any preference between this and the other suggestion, im just
> > providing some alternatives. The above is pretty simple so if it works
> for
> > you i can write up a patch for that pretty easily.
>
> I'm not sure why libressl sets OPENSSL_VERSION_NUMBER to 0x20000000L.
> Maybe so that they can pick and choose which openssl APIs to implement
> (rather than everything up through some version)?
>
> I'm fine with any of the suggested approaches. I just went with
> !defined(LIBRESSL_VERSION_NUMBER) in my original patch because that's
> what I've seen projects like curl, wpa_supplicant, and openvpn do. It
> also seems to be what openbsd is doing itself with patches in its
> ports tree (xca, stunnel, postfix).
>

Something should actually be done about this. Im fine with the original
patch but the blocker seems to have been Michael. Im not such a huge fan of
cluttering configure and slowing it down more for a small issue (as there
could get progressively more and more difference between the 2 projects) so
as an inbetween what about creating HAVE_BIO_METHODS but do so only locally
in tls_openssl using something like:

#if OPENSSL_VERSION_NUMBER >= 0x1010000fL && !defined(LIBRESSL_VERSION_
NUMBER)
#define HAVE_BIO_METHODS_WHATEVER 1
#else
#define HAVE_BIO_METHODS_WHATEVER 0
#endif