chore: upgrade libghostty and preserve terminal behavior (#3906)

1 files changed, 28 insertions, 0 deletions

diff --git a/vendor/libghostty-vt/src/lib/c_abi.zig b/vendor/libghostty-vt/src/lib/c_abi.zig
new file mode 100644
index 00000000..3ce34754
--- /dev/null
+++ b/vendor/libghostty-vt/src/lib/c_abi.zig
@@ -0,0 +1,28 @@
+//! Memory-layout properties shared with C API callers.
+//!
+//! The C ABI defines how values are represented in memory so code written in
+//! different languages can safely exchange them. One part of that contract is
+//! alignment: some values must begin at an address divisible by 2, 4, 8, or
+//! another power of two. Reading a value from a less-aligned address can be
+//! slow on some CPUs and invalid on others.
+//!
+//! This module derives those properties from Zig's compile-time target data.
+//! It does not call or link libc. Keeping the calculation here gives allocators
+//! and ABI metadata one source of truth.
+
+const std = @import("std");
+const builtin = @import("builtin");
+
+/// Largest address alignment required by a fundamental C ABI type, in bytes.
+///
+/// For example, a value of 16 means storage intended to hold an arbitrary C
+/// value must begin at an address evenly divisible by 16. The Wasm allocator
+/// uses this value for caller-owned ABI storage, and `ghostty_type_json`
+/// publishes it so hosts know the guarantee made by that allocator.
+pub const max_alignment: u16 = max: {
+    var result: u16 = @alignOf(*anyopaque);
+    for (std.enums.values(std.Target.CType)) |c_type| {
+        result = @max(result, builtin.target.cTypeAlignment(c_type));
+    }
+    break :max result;
+};