In several modules we build up an RB tree keyed by wide characters.
wchar_t has different signedness on different platforms, so iteration
over such a tree results in platform-dependent ordering.
The ctype module uses this ordering when writing the output file, which
creates reproducibility problems when comparing the results of cross
builds and native builds (e.g., native amd64 vs. cross-building on
arm64).
Modify such comparisons to always be unsigned. Introduce a helper
function for this purpose. In the other modules I believe the sort
order does not affect program output.