This is an auto-filled bug because dev-libs/ustr calls ranlib directly.
The issue was originally discovered on amd64, 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 RANLIB implementation (like llvm-ranlib) by setting the RANLIB variable. So this issue has been reproduced by setting the RANLIB variable to x86_64-pc-linux-gnu-ranlib and by removing the /usr/bin/ranlib binary.
Created attachment 639134 [details]
build log and emerge --info
*** This bug has been marked as a duplicate of bug 719160 ***