mpv, ffmpeg: use addOpenGLRunpath to fix CUDA-accelerated playback

This fixes #67780.

Currently, using `mpv --hwdec=nvdec --msg-level=vd=debug` on NVIDIA results in:

```
[vd] Opening decoder hevc
[vd] Looking at hwdec hevc-nvdec...
Cannot load libcuda.so.1
[vd] Could not create device.
[vd] No hardware decoding available for this codec.
```

With just mpv patched, ffmpeg cannot load libnvcuvid.so.1:

```
[vd] Opening decoder hevc
[vd] Looking at hwdec hevc-nvdec...
[vd] Trying hardware decoding via hevc-nvdec.
[vd] Selected codec: hevc (HEVC (High Efficiency Video Coding))
[vd] Pixel formats supported by decoder: vaapi_vld cuda yuv420p10le
[vd] Codec profile: Main 10 (0x2)
[vd] Requesting pixfmt 'cuda' from decoder.
[ffmpeg/video] hevc: Cannot load libnvcuvid.so.1
[ffmpeg/video] hevc: Failed loading nvcuvid.
[ffmpeg/video] hevc: Failed setup for format cuda: hwaccel initialisation returned error.
```

With both mpv and ffmpeg patched, it works:

```
[vd] Opening decoder hevc
[vd] Looking at hwdec hevc-nvdec...
[vd] Trying hardware decoding via hevc-nvdec.
[vd] Selected codec: hevc (HEVC (High Efficiency Video Coding))
[vd] Pixel formats supported by decoder: vaapi_vld cuda yuv420p10le
[vd] Codec profile: Main 10 (0x2)
[vd] Requesting pixfmt 'cuda' from decoder.
Using hardware decoding (nvdec).
[vd] Decoder format: 3840x2160 cuda[p010] bt.2020-ncl/bt.2020/pq/limited/auto SP=10.000000 CL=unknown (auto 0.000000/0.000000/0.000000)
```