various fixes for macos

src/Window.zig

@@ -6,6 +6,7 @@
 const Window = @This();
 
 const std = @import("std");
+const builtin = @import("builtin");
 const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const Grid = @import("Grid.zig");
@@ -55,6 +56,7 @@ pub fn create(alloc: Allocator, loop: libuv.Loop) !*Window {
         .context_version_minor = 3,
         .opengl_profile = .opengl_core_profile,
         .opengl_forward_compat = true,
+        .cocoa_graphics_switching = builtin.os.tag == .macos,
     });
     errdefer window.destroy();
 

src/libuv/Embed.zig

@@ -105,7 +105,7 @@ fn threadMain(self: *Embed) void {
             .macos, .dragonfly, .freebsd, .openbsd, .netbsd => {
                 var ts: std.os.timespec = .{
                     .tv_sec = @divTrunc(timeout, 1000),
-                    .tv_nsec = @mod(timeout, 1000) * 1000,
+                    .tv_nsec = @mod(timeout, 1000) * 1000000,
                 };
 
                 var ev: [0]std.os.Kevent = undefined;