Bug#456165: Please add dvdnav_dup() and dvdnav_free_dup() functions from the handbrake project

[Fabian Greffrath]

Dear libdvdnav devs,

please consider applying the following patch originating from the
handbrake project:
<https://github.com/HandBrake/HandBrake/blob/master/contrib/libdvdnav/A08-dvdnav-dup.patch>

It adds two new functions, dvdnav_dup() and dvdnav_free_dup(), that
duplicate a dvdnav_t object and remove a duplicate from memory,
respectively - well, at least roughly.

We (i.e. the pkg-multimedia-packages team in Debian) are currently trying
to get handbrake built cleanly against Debian's system libraries and this
patch is currently the only one that's missing to reach this goal. The
handbrake build system currently downloads the libdvdnav source code
(among others), patches it and builds a private library from it. Adding
the functions directly into the handbrake source code (instead of the
downloaded library) is impossible, because they need to know
sizeof(dvdnav_t), which is not part of libdvdnav's public API - which is
in turn reasonable.

So, please, having these two functions in the next libdvdnav release would
make it possible to build this huge OSS project that is handbrake using
only the distribution's libraries (apart from libfaac, of course, which is
prepared but still not in Debian, because it is considered non-free by our
FTP-Masters).

BTW, there are also some other interesting patches in handbrake's repos. ;)

Best regards,
Fabian