As of now `gtk4-layer-shell` is unavailable on recent, stable releases
of many distros (Debian 12, Ubuntu 24.04, openSUSE Leap & Tumbleweed, etc.)
and outdated on many others (Nixpkgs 24.11/unstable, Fedora 41, etc.)
This is inconvenient for our users and severely limits where the quick
terminal can be used. As a result we then build gtk4-layer-shell ourselves
by default unless `--system` or `-fsys=gtk4-layer-shell` are specified.
This also allows me to add an idiomatic Zig API on top of the library
and avoiding adding even more raw C code in the GTK apprt.
Since we now build gtk4-layer-shell it should be theoretically available
on all Linux systems we target. As such, the `-Dgtk-layer-shell` build
option has been removed. This is somewhat of an experimental change as
I don't know if gtk4-layer-shell works perfectly across all distros, and
we can always add the option back if need be.
Using `gtk4-layer-shell` still seems like the path of least resistance,
and to my delight it pretty much Just Works. Hurrah!
This implementation could do with some further polish (e.g. animations,
which can be implemented via libadwaita's animations API, and global
shortcuts), but as a MVP it works well enough.
It even supports tabs!
Fixes#4624.
The major idea behind the refactor is to split the `build.zig` file up into
distinct `src/build/*.zig` files. By doing so, we can improve readability of
the primary `build.zig` while also enabling better reuse of steps. Our
`build.zig` is now less than 150 lines of code (of course, it calls into a lot
more lines but they're neatly organized now).
Improvements:
* `build.zig` is less than 150 lines of readable code.
* Help strings and unicode table generators are only run once when multiple
artifacts are built since the results are the same regardless of target.
* Metal lib is only built once per architecture (rather than once per artifact)
* Resources (shell integration, terminfo, etc.) and docs are only
built/installed for artifacts that need them
Breaking changes:
* Removed broken wasm build (@gabydd will re-add)
* Removed conformance files, shell scripts are better and we don't run
these anymore
* Removed macOS app bundle creation, we don't use this anymore since we
use Xcode
## Some History
Our `build.zig` hasn't been significantly refactored since the project started,
when Zig was _version 0.10_. Since then, the build system has changed
significantly. We've only ever duct taped the `build.zig` as we needed to
support new Zig versions, new features, etc. It was a mess.
The major improvement is adapting the entire Ghostty `build.zig` to the Step
and LazyPath changes introduced way back in Zig 0.12. This lets us better take
advantage of parallelism and the dependency graph so that steps are only
executed as they're needed.
As such, you can see in the build.zig that we initialize a lot of things, but
unless a final target (i.e. install, run) references those steps, _they'll
never be executed_. This lets us clean up a lot.
