zig: update to version 0.13.0

[sugarthc]

- Update to version 0.13.0
- Force static linking of llvm/clang; this was the default previously
- Since llvm/clang are linking statically these can be build-only dependencies.

Closes: https://trac.macports.org/ticket/70584
Supersedes: https://github.com/macports/macports-ports/pull/24430 (draft)

Description

Type(s)

• [ ] bugfix
• [ ] enhancement
• [ ] security fix

Tested on

macOS 13.6.9 22G830 x86_64 Xcode 15.2 15C500b

macOS 14.6.1 23G93 arm64 Xcode 15.4 15F31d

Verification

Have you

• [x] followed our Commit Message Guidelines?
• [x] squashed and minimized your commits?
• [x] checked that there aren't other open pull requests for the same change?
• [x] referenced existing tickets on Trac with full URL in commit message?
• [x] checked your Portfile with port lint --nitpick?
• [x] tried existing tests with sudo port test?
• [x] tried a full install with sudo port -vst install?
• [x] tested basic functionality of all binary files?
• [ ] checked that the Portfile's most important variants haven't been broken?

There is a draft PR for this that seems to have died on the vine.