vt: expose optimize mode in build info API

Add GHOSTTY_BUILD_INFO_OPTIMIZE to query the Zig optimization mode
(debug, release safe/small/fast) the library was compiled with. This
reads directly from builtin.mode at comptime so it requires no build
system plumbing.

include/ghostty/vt/build_info.h

@@ -31,6 +31,16 @@
 extern "C" {
 #endif
 
+/**
+ * Build optimization mode.
+ */
+typedef enum {
+  GHOSTTY_OPTIMIZE_DEBUG = 0,
+  GHOSTTY_OPTIMIZE_RELEASE_SAFE = 1,
+  GHOSTTY_OPTIMIZE_RELEASE_SMALL = 2,
+  GHOSTTY_OPTIMIZE_RELEASE_FAST = 3,
+} GhosttyOptimizeMode;
+
 /**
  * Build info data types that can be queried.
  *
@@ -60,6 +70,13 @@ typedef enum {
    * Output type: bool *
    */
   GHOSTTY_BUILD_INFO_TMUX_CONTROL_MODE = 3,
+
+  /**
+   * The optimization mode the library was built with.
+   *
+   * Output type: GhosttyOptimizeMode *
+   */
+  GHOSTTY_BUILD_INFO_OPTIMIZE = 4,
 } GhosttyBuildInfo;
 
 /**

src/terminal/c/build_info.zig

@@ -1,21 +1,32 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const build_options = @import("terminal_options");
 const Result = @import("result.zig").Result;
 
 const log = std.log.scoped(.build_info_c);
 
+/// C: GhosttyOptimizeMode
+pub const OptimizeMode = enum(c_int) {
+    debug = 0,
+    release_safe = 1,
+    release_small = 2,
+    release_fast = 3,
+};
+
 /// C: GhosttyBuildInfo
 pub const BuildInfo = enum(c_int) {
     invalid = 0,
     simd = 1,
     kitty_graphics = 2,
     tmux_control_mode = 3,
+    optimize = 4,
 
     /// Output type expected for querying the data of the given kind.
     pub fn OutType(comptime self: BuildInfo) type {
         return switch (self) {
             .invalid => void,
             .simd, .kitty_graphics, .tmux_control_mode => bool,
+            .optimize => OptimizeMode,
         };
     }
 };
@@ -48,6 +59,12 @@ fn getTyped(
         .simd => out.* = build_options.simd,
         .kitty_graphics => out.* = build_options.kitty_graphics,
         .tmux_control_mode => out.* = build_options.tmux_control_mode,
+        .optimize => out.* = switch (builtin.mode) {
+            .Debug => .debug,
+            .ReleaseSafe => .release_safe,
+            .ReleaseSmall => .release_small,
+            .ReleaseFast => .release_fast,
+        },
     }
 
     return .success;
@@ -74,6 +91,18 @@ test "get tmux_control_mode" {
     try testing.expectEqual(build_options.tmux_control_mode, value);
 }
 
+test "get optimize" {
+    const testing = std.testing;
+    var value: OptimizeMode = undefined;
+    try testing.expectEqual(Result.success, get(.optimize, @ptrCast(&value)));
+    try testing.expectEqual(switch (builtin.mode) {
+        .Debug => .debug,
+        .ReleaseSafe => .release_safe,
+        .ReleaseSmall => .release_small,
+        .ReleaseFast => .release_fast,
+    }, value);
+}
+
 test "get invalid" {
     try std.testing.expectEqual(Result.invalid_value, get(.invalid, null));
 }