Setting compiler flags to +DD64 produces 64-bit objects, but the linker does not understand this flag, so either you'll see an ld failure to recognize +DD64 at link time, or you'll see a failure later mixing 32 and 64-bit objects.

I also modified the C++ variable because that's obviously needed as well.
There was an issue with configure - after modifying one and adding another line in configure.ac, autoconf 2.69 removed all instances of "runstatedir" in the generated configure script, so I made my intended change to configure in an editor as well.