Update tzcode to 2025b

[des]

Summary

MFC after: 3 weeks

[des]

At some point we should evaluate the differences between tzcode's strftime.c and ours and consider switching.

[philip]

This looks good. I agree about strftime.c.

My build test is still running. I'll try to take a look at the results later today. Otherwise tomorrow.

[des]

rebase

[des]

fix inverted issetugid logic

[des]

See D52124 for additional tests

[des]

fix

[philip]

This compiles and the "git diff" output against upstream and against main looks plausible. I have not checked every line of the diff with a fine tooth comb. But this can land. I don't think it will break.

[des]

fix jail case