-1 for your change issue25658-1.patch.
It adds a O(n) slowdown to PyThread_set_key_value() whereas the performance of this function matters. Moreover, the code currently works fine on Linux, I fail to see why we should make Python slower to support a new platform.
The PEP 11 explains the criteria to support a new platform in Python. Before we start to officially support CloudABI, you should start to work on a fork. When you will get enough users and have a better view of all requires changes, you can come back with a full plan to support officially this platform.