invalid ELF class 2; expected 1

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

After upgrading to NetBSD 8.1, a screen binary built for NetBSD 8.0
ceased to work:

As non privilegied user:
$ /usr/pkg/bin/screen-4.6.2
/bin/sh: Can't open /usr/pkg/bin/screen-4.6.2

As root (screen is setuid with mode 4555)
# /usr/pkg/bin/screen-4.6.2
/bin/sh: Cannot execute ELF binary /usr/pkg/bin/screen-4.6.2
# ldd /usr/pkg/bin/screen-4.6.2
ldd: /usr/pkg/bin/screen-4.6.2: invalid ELF class 2; expected 1

What does that mean? It seems to happen on amd64 but not on i386.

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost