Add a ghostty_vt_add_target() CMake function that lets downstream
projects build libghostty-vt for a specific Zig target triple. The
function encapsulates zig discovery, build-type-to-optimize mapping,
the zig build invocation, and output path conventions so consumers
do not need to duplicate any of that logic. It creates named IMPORTED
targets (e.g. ghostty-vt-static-linux-amd64) that work alongside the
existing native ghostty-vt and ghostty-vt-static targets.
The build-type mapping is factored into a shared _GHOSTTY_ZIG_OPT_FLAG
variable used by both the native build and the new function.
The static library targets now propagate c++ as a link dependency on
non-Windows platforms, fixing link failures when consumers use static
linking with the default SIMD-enabled build.
A new example/c-vt-cmake-cross/ demonstrates end-to-end cross-
compilation using zig cc as the C compiler, auto-detecting a cross
target based on the host OS.
Remove the dedicated `zig build lib-vt` step and replace it with a
`-Demit-lib-vt` build option. This fixes two problems:
1. We can default XCFramework, app, etc. steps to false if emit-lib-vt
is true, so that the lib-vt build doesn't pull in unrelated
artifacts. **Most importantly, lib-vt alone can be build without
full Xcode installations.**
2. We can build lib-vt as part of a bundle with other artifacts if we
really want.
Add a top-level CMakeLists.txt that wraps `zig build lib-vt` so that
CMake-based downstream projects can consume libghostty-vt without
needing to interact with the Zig build system directly. A custom
command triggers the zig build during `cmake --build`, and the
resulting shared library is exposed as an IMPORTED target.
Downstream projects can pull in the library via FetchContent, which
fetches the source and builds it as part of their own CMake build, or
via find_package after a manual install step. The package config
template in dist/cmake/ sets up the ghostty-vt::ghostty-vt target
with proper include paths and macOS rpath handling.
A c-vt-cmake example demonstrates the FetchContent workflow, creating
a terminal, writing VT sequences, and formatting the output as plain
text. CI is updated to auto-discover and build CMake-based examples
alongside the existing Zig-based ones.
