I want to say Oracle database clients as an example.
My company definitely had problems to get database drivers to work generally speaking and on both 32 bits and 64 bits. Have a look at postgres, oracle, cassandra, redis, sybase to name a few, I am not sure which one was worse, it wasn't me doing the work. But I've seen some of the C and C++ dependencies that needed to compile with the errors that happened and that was horrendous.