bug#75237: Packaging ghostty terminal

["Murilo" via Bug reports for GNU Guix <bug-guix@gnu.org>]

I essentially gave up on packaging ghostty for upstreaming, already spent too
much time on this so I'm moving on.
Will continue to update the current working version on my channel, for personal
use.
Here's my WIP guix branch for ghostty if someone wants to give it a shot, in the
hopes that it might be useful for someone:

https://codeberg.org/look/guix/src/branch/wip-ghostty
https://codeberg.org/look/guix/commits/branch/wip-ghostty

Some zig dependencies there already meet the upstreaming requirements.

The ghostty package does not build, getting some strange errors because of
libvaxis, and missing some zig-mach dependencies.

Might experience some version mismatches because I'm initially using the C
packages we already have packaged on guix.

It needs wuffs which is going to be pain :-(.

The 'fix-path phase substitute* does not work, can be removed, was something I
was experimenting with.

The 'hard-disable-macos-dependencies is also an experiment, might not work.