We found with Python 3.15.0rc1 and Ubuntu 26.04 that ctypes was missing.
[ERROR] _ctypes failed to import: /tmp/buildpy/python-prefix/src/python-build/build/lib.linux-aarch64-3.15/_ctypes.cpython-315-aarch64-linux-gnu.so: undefined symbol: ffi_type_void
[ERROR] _ctypes (/tmp/buildpy/python-prefix/src/python-build/build/lib.linux-aarch64-3.15/_ctypes.cpython-315-aarch64-linux-gnu.so) is missing
The necessary bits to build these optional modules were not found:
_dbm _gdbm _tkinter
To find the necessary bits, look in configure.ac and config.log.
Following modules built successfully but were removed because they could not be imported:
_ctypes
This is handled in ffi.cmake by checking the FFI version.nm