This is an auto-filled bug because media-libs/libmpeg2 calls nm directly.
The issue was originally discovered on arm64, but it may be reproducible on other arches as well.
If you think that a different summary clarifies the issue better, feel free to change it.
Attached build log and emerge --info.
If you think it doesn't make sense fix these type of issues, I'd like to point out that won't be possible use a different NM implementation (like llvm-nm) by setting the NM variable. So this issue has been reproduced by setting the NM variable to aarch64-unknown-linux-gnu-nm and by removing the /usr/bin/nm binary.
Created attachment 635910 [details]
build log and emerge --info