This bug is marked as Fix Released in Focal (20.04) but it is not fixed as of January 22. libc6-dev, the package that provides tgmath.h is still 2.31, and it seems the fix was introduced in 2.32, which is not available on 20.04 repos.
This bug is marked as Fix Released in Focal (20.04) but it is not fixed as of January 22. libc6-dev, the package that provides tgmath.h is still 2.31, and it seems the fix was introduced in 2.32, which is not available on 20.04 repos.