mac: get default click repeat interval from NSEvent

src/config.zig

@@ -5,6 +5,7 @@ const ArenaAllocator = std.heap.ArenaAllocator;
 const inputpkg = @import("input.zig");
 const passwd = @import("passwd.zig");
 const terminal = @import("terminal/main.zig");
+const internal_os = @import("os/main.zig");
 
 const log = std.log.scoped(.config);
 
@@ -327,7 +328,7 @@ pub const Config = struct {
 
         // Default our click interval
         if (self.@"click-repeat-interval" == 0) {
-            self.@"click-repeat-interval" = 500;
+            self.@"click-repeat-interval" = internal_os.clickInterval() orelse 500;
         }
     }
 };

src/os/main.zig

@@ -4,3 +4,4 @@
 pub usingnamespace @import("file.zig");
 pub usingnamespace @import("locale.zig");
 pub usingnamespace @import("macos_version.zig");
+pub usingnamespace @import("mouse.zig");

src/os/mouse.zig

@@ -0,0 +1,24 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const assert = std.debug.assert;
+const objc = @import("objc");
+
+const log = std.log.scoped(.os);
+
+/// The system-configured double-click interval if its available.
+pub fn clickInterval() ?u32 {
+    // On macOS, we can ask the system.
+    if (comptime builtin.target.isDarwin()) {
+        const NSEvent = objc.Class.getClass("NSEvent") orelse {
+            log.err("NSEvent class not found. Can't get click interval.", .{});
+            return null;
+        };
+
+        // Get the interval and convert to ms
+        const interval = NSEvent.msgSend(f64, objc.sel("doubleClickInterval"), .{});
+        const ms = @floatToInt(u32, @ceil(interval * 1000));
+        return ms;
+    }
+
+    return null;
+}