We won't be able to support CMake (or ndk-build) on 32 bit OS because it is not supported in CLion which is the tech we use for the C++ editor. The root cause is memory\address-space limits.
Here's a helper page where I describe Android Studio C++ support including the 64 bit requirement: https://sites.google.com/a/android.com/tools/tech-docs/external-c-builds
I hope this helps! - Jomo