CDP beta linux sources are 64-bit. Unfortunately, my older cpu only supports 32-bit. Tried compiling before I realized this issue.
Are you getting compiler errors? That might be because of using an old compiler. Or is there some other issue? The binaries build but they don't work on your 32 bit system?
I don't see any obvious reason how the source codes themselves would be "64 bit only". By "64 bit compatible" they probably mean the code doesn't use pointer tricks and such that only used to work with 32 bit CPUs. (It says "64 bit compatible" on the CDP download page, not "64 bit only"...)
I can test compiling for 32 bit on my Ubuntu 16 laptop to confirm.
edit : OK, so I tested building on my 32(*) bit Ubuntu system with GCC 5.3.1. The built binaries actually end up as 32 bit ones and I didn't need to do anything special for that to happen. I doubt the CDP programs would benefit from being compiled into 64 bit in any case. I only tried building "modify" and "sfedit" so far because I didn't want to first install/build the external dependencies nor wait for all the CDP programs to build. (My Linux laptop is quite slow.)
(*) Mistake there before. The laptop actually has 32 bit Ubuntu installed.