Hi there, this is just a low-hanging fruit and it also prepares the way for the future 0.15, which removes addStaticLibrary. Please, let me know what to do on the `// TODO` comments.
This fixes an issue where Ghostty would not build against the macOS 15.5 SDK. What was happening was that Zig was adding its embedded libc paths to the clang command line, which included old headers that were incompatible with the latest (macOS 15.5) SDK. Ghostty was adding the newer paths but they were being overridden by the embedded libc paths. The reason this was happening is because Zig was using its own logic to find the libc paths and this was colliding with the paths we were setting manually. To fix this, we now use a `libc.txt` file that explicitly tells Zig where to find libc, and we base this on our own SDK search logic.
Lazy dependencies are only fetched if the build script would actually reach a usage of that dependency at runtime (when the `lazyDependency` function is called). This can save a lot of network traffic, disk uage, and time because we don't have to fetch and build dependencies that we don't actually need. Prior to this commit, Ghostty fetched almost everything for all platforms and configurations all the time. This commit reverses that to fetching almost nothing until it's actually needed. There are very little downsides to doing this[1]. One downside is `zig build --fetch` doesn't fetch lazy dependencies, but we don't rely on this command for packaging and suggest using our custom shell script that downloads a cached list of URLs (`build.zig.zon.txt`). This commit doesn't cover 100% of dependencies, since some provide no benefit to make lazy while the complexity to make them lazy is higher (in code style typically). Conversely, some simple dependencies are marked lazy even if they're almost always needed if they don't introduce any real complexity to the code, because there is very little downside to do so. [1]: https://ziggit.dev/t/lazy-dependencies-best-dependencies/5509/5
This gets `zig build -Dtarget=aarch64-ios` working. By "working" I mean it produces an object file without compiler errors. However, the object file certainly isn't useful since it uses a number of features that will not work in the iOS sandbox. This is just an experiment more than anything to see how hard it would be to get libghostty working within iOS to render a terminal. Note iOS doesn't support ptys so this wouldn't be a true on-device terminal. The challenge right now is to just get a terminal rendering (not usable).