There is a new pull request by ericonr against master on the void-packages repository

https://github.com/ericonr/void-packages ffmpeg
https://github.com/void-linux/void-packages/pull/23542

[RFC][NOMERGE] Update libaom and enable it for ffmpeg
Fixes #23538 

I currently get segfaults when trying to use this with ffmpeg.

```
$ ffmpeg -i example.mp4 -c:v libaom-av1 -crf 30 -b:v 0 -strict experimental av1_test.mkv
```

gets me this backtrace:

```
#0  0x00007f98d9dde6c0 in lowbd_inv_txfm2d_add_no_identity_avx2 () from /lib/libaom.so.2
#1  0x00007f98d9b6b449 in av1_inverse_transform_block () from /lib/libaom.so.2
#2  0x00007f98d9d04eb1 in search_tx_type.constprop () from /lib/libaom.so.2
#3  0x00007f98d9d08cf6 in block_rd_txfm () from /lib/libaom.so.2
#4  0x00007f98d9c53f1f in av1_foreach_transformed_block_in_plane () from /lib/libaom.so.2
#5  0x00007f98d9d0de79 in av1_txfm_rd_in_plane () from /lib/libaom.so.2
#6  0x00007f98d9d0e006 in av1_uniform_txfm_yrd () from /lib/libaom.so.2
#7  0x00007f98d9d0e5ee in choose_tx_size_type_from_rd () from /lib/libaom.so.2
#8  0x00007f98d9d0e996 in av1_pick_uniform_tx_size_type_yrd () from /lib/libaom.so.2
#9  0x00007f98d9d1aaaa in av1_rd_pick_intra_sby_mode () from /lib/libaom.so.2
#10 0x00007f98d9ce402a in av1_rd_pick_intra_mode_sb () from /lib/libaom.so.2
#11 0x00007f98d9c361f1 in pick_sb_modes () from /lib/libaom.so.2
#12 0x00007f98d9c3b64e in rd_use_partition () from /lib/libaom.so.2
#13 0x00007f98d9c3af86 in rd_use_partition () from /lib/libaom.so.2
#14 0x00007f98d9c3b174 in rd_use_partition () from /lib/libaom.so.2
#15 0x00007f98d9c49eba in encode_rd_sb () from /lib/libaom.so.2
#16 0x00007f98d9c4e4a9 in av1_encode_sb_row () from /lib/libaom.so.2
#17 0x00007f98d9c7e002 in enc_row_mt_worker_hook () from /lib/libaom.so.2
#18 0x00007f98d9b2986b in thread_loop () from /lib/libaom.so.2
#19 0x00007f98dd1fa305 in start (p=0x7f98aec3a7a8) at src/thread/pthread_create.c:192
#20 0x00007f98dd207a6b in __clone () at src/thread/x86_64/clone.s:22
Backtrace stopped: frame did not save the PC
quit
```

I'm not sure we can enable it when it's like this. I can try using FFMPEG 4.3 to see if it works better then. I am on musl, so that might be an issue.

I also don't know how to test for gstreamer AV1 support. 

A patch file from https://github.com/void-linux/void-packages/pull/23542.patch is attached