Update Zig to 0.14.0 and Ncdu to 2.8 to fix build errors + LLVM 20 breaks Zig build requirements

[hpaluch]

Here is patch that makes 2 version upgrades to again build Ncdu (full screen disk usage utility) without error.

1. Ncdu upgraded from 2.0.1 to 2.8 to fix several major incompatibilities with Zig 0.14dev+ - contributed
   by "BratishkaErik" on https://code.blicky.net/yorhel/ncdu/pulls/254 - these are included in Ncdu 2.8 release
2. Zig upgraded from 0.14.0-dev.2546+0ff0bdb4a to 0.14.0 to support std.debug.FullPanic on which Ncdu 2.8 now depends.

Warning

1. Above Zig upgrade may break other packages depending on it!
2. With latest SVN Trunk it is no longer possible to build any version of Zig, because Zig requires LLVM 19.x while current Trunk upgrades to LLVM 20.1.0. I don't know how to resolve this problem. There is PR in Zig project at LLVM 20 ziglang/zig#22780 but is is not finished (Draft).

So I'm currently using this dirty trick to build Zig and Ncdu under latest trunk:

• I install T2 version 25.1 from t2-25.1-x86-64-base-wayland-glibc-gcc-nocona.iso
• I update sources with t2 up but I don't upgrade LLVM in system (so it stays on 19.1.7)
• finally I run:

t2 install zig
t2 install ncdu

Please consider above risks before merging this PR.

[rxrbln]

Thanks you for your contribution. Looks good, t2 commit update some (C) and .cache:
Committed revision 75109 and 75110.