Make stuff work more easily on Linux/ROCm

[infinity0]

With my relatively new AMD Radeon RX 7800 XT I need to set the following envvars for ROCm to work:

export PYTORCH_HIP_ALLOC_CONF=expandable_segments:True
export HSA_OVERRIDE_GFX_VERSION=11.0.0
export HCC_AMDGPU_TARGET=gfx1101

Instead of hardcoding this all, just pass the whole parent environment in, this is the default behaviour anyway for most "spawn" APIs.

Also torchaudio can't detect my ffmpeg 7, it seems to not support this yet. libsox-dev works as an alternative.

Now I can demux stems in 20 seconds compared to 10 minutes for Wine/CPU! :D