ffmpeg4 build problems

[Robert Swindells <rjs%fdy2.co.uk@localhost>]

I am seeing errors on aarch64 when multimedia/mplayer tries to load one
of the ffmpeg4 libraries:

/usr/pkg/lib/ffmpeg4/libavcodec.so.58: text relocations
Segmentation fault (core dumped)

I have built ld.elf_so with debugging enabled but it doesn't really give
me an idea of which where the bad relocations have come from.

...
fixup !main in /usr/pkg/lib/ffmpeg4/libavformat.so.58 --> 0xfffffb8b88e0
fixup !main in /usr/pkg/lib/ffmpeg4/libavformat.so.58 --> 0xfffffb8b88e0
fixup !main in /usr/pkg/lib/ffmpeg4/libavformat.so.58 --> 0xfffffb8b88e0
fixup !main in /usr/pkg/lib/ffmpeg4/libavformat.so.58 --> 0xfffffb8b88e0
fixing up PLTGOT
 relocating /usr/pkg/lib/ffmpeg4/libavcodec.so.58 (0/17195 rel/rela, 0/441 plt rel/rela)
/usr/pkg/lib/ffmpeg4/libavcodec.so.58: text relocations
doing non-PLT relocations

The segv is coming from _rtld_relocate_nonplt_objects().

I don't think that ld.elf_so should crash with this input but there
seems to be something wrong with my build of ffmpeg4 too.