Now that the compat4x libc.so.4 binary has been updated, we can finally
switch over to using a future-proof stdin/out/err.

Note that if you run 4.x binaries on your system, you will certainly
want to update /usr/lib/compat/libc.so.4. The easiest way is to
add "COMPAT4X= yes" in your /etc/make.conf.