nix - multiple issues, broken on both 32-bit and 64-bit, see https://slackware.uk/~urchlay/src/nix.32bit.fail.log and https://slackware.uk/~urchlay/src/nix.64bit.write.to.usr.log
openjdk6 - same issue as openjdk7.
openjdk7 - FTBFS, it's using gcc-5, but trying to link with /usr/lib/libstdc++.so instead of the one in /usr/lib/gcc/i586-slackware-linux/5.5.0/libstdc++.so
openjdk8 - can't test, needs openjdk8 first.