Recently, I tried to set up `dcv` with `dub` to improve a few
things in the library, but I faced some strange issues.
When doing `dub add dcv`, it works fine. But when I try to add a
local dcv project folder, or a repository, it fails to link the
necessary package libraries. Seems like it's only `ffmpeg`
libraries that are not linked.
What am I missing here?
```
// dub.json
...
"dependencies": {
"dcv": {
"repository": "git+https://github.com/rillki/dcv.git";,
"version": "~master"
}
},
...
```
Output:
```
Undefined symbols for architecture x86_64:
"_av_free_packet", referenced from:
__D3dcv7videoio5input11InputStream13readFrameImplMFNbNiKCQCc4core5image5ImageZb in libdcv.a(input_2c65_47c.o)
__D3dcv7videoio6output12OutputStream__T10writeSliceTS3mir7ndslice5slice__T9mir_sliceTPhVmi2VEQBoQBnQBi14mir_slice_kindi2ZQBvZQDiMFNbNiQDeEQFf4core5image11ImageFormatZb in libdcv.a(output_2c76_14e7.o)
__D3dcv7videoio6output12OutputStream__T10writeSliceTS3mir7ndslice5slice__T9mir_sliceTPhVmi3VEQBoQBnQBi14mir_slice_kindi2ZQBvZQDiMFNbNiQDeEQFf4core5image11ImageFormatZb in libdcv.a(output_2c74_14e8.o)
"_av_register_all", referenced from:
__D3dcv7videoio6common9AVStarter6__ctorMFNbNiZCQBsQBrQBmQBi
in libdcv.a(common_2c56_37c.o)
"_avcodec_decode_video2", referenced from:
ETC....
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to
see invocation)
Error: linker exited with status 1
Error dmd failed with exit code 1.
```
