rust on PowerPC

Hi,

lang/rust on evbppc running NetBSD 11.99.5 gives:

Building bootstrap
/usr/pkgsrc/lang/rust/work/rust-bootstrap/bin/cargo: Shared object "libatomic.so.3" not found

libatomic is installed:

pkg_info | grep libatomic
libatomic-15.1.0    Atomic fallback implementation for GCC
libatomic-links-1.1 Make libatomic available from a unique directory

find / -name libatomic.so\* -print
/usr/pkgsrc/lang/rust/work/.buildlink/lib/libatomic.so
/usr/pkgsrc/lang/rust/work/.buildlink/lib/libatomic.so.3
/usr/pkgsrc/lang/rust/work/.buildlink/lib/libatomic.so.3.0
/usr/pkgsrc/lang/rust/work.bad/.buildlink/lib/libatomic.so
/usr/pkgsrc/lang/rust/work.bad/.buildlink/lib/libatomic.so.3
/usr/pkgsrc/lang/rust/work.bad/.buildlink/lib/libatomic.so.3.0
/usr/local/lib/libatomic.so
/usr/local/lib/libatomic.so.3
/usr/local/lib/libatomic.so.3.0
/usr/local/lib/libatomic/libatomic.so
/usr/local/lib/libatomic/libatomic.so.3
/usr/local/lib/libatomic/libatomic.so.3.0

I've seen this before, but I've forgotten why it happens or how to fix it. 
Can anyone help remind me?

Thanks,
John