[ODE] ODE on x86_64 machine

[steve1011]

I think you are using the 0.5 stable release. I changed all loss of 
precision errors to ulong and got it to compile. There are a lot of 
them. Header files too.

Or, if you work with the unstable release you won't have to change 
anything, except for the make file reference to the X11 library. You 
will want to use the 64 bit version. I don't know what you do for MS 
Windows since it doesn't use X.