* gnu/packages/zig.scm (zig-0.10): New variable.
(zig-0.9): Rename from zig. Inherit from zig-0.10.
(zig): Define as zig-0.10.
* gnu/packages/ncdu.scm (ncdu)[native-inputs]: Use zig-0.9.
* gnu/packages/zig-xyz.scm (zig-zls)[inputs]: Use zig-0.9.
* gnu/packages/ncdu.scm (ncdu-1): New variable, renamed from…
(ncdu): …this one, itself renamed from the old ncdu-2. Simple!
[name]: Drop suffix.
[properties]: Remove obsolete 'upstream-name.
(ncdu-2): Redefine as a DEPRECATED-PACKAGE alias of ncdu.