mach: use pure-Zig mach-gamemode package

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

build.zig

@@ -4,7 +4,6 @@ const system_sdk = @import("libs/glfw/system_sdk.zig");
 const glfw = @import("libs/glfw/build.zig");
 const freetype = @import("libs/freetype/build.zig");
 const basisu = @import("libs/basisu/build.zig");
-const gamemode = @import("libs/gamemode/build.zig");
 const model3d = @import("libs/model3d/build.zig");
 pub const gpu_dawn = @import("libs/gpu-dawn/sdk.zig").Sdk(.{
     .glfw_include_dir = sdkPath("/libs/glfw/upstream/glfw/include"),
@@ -20,7 +19,6 @@ const core = @import("libs/core/sdk.zig").Sdk(.{
     .gpu = gpu,
     .gpu_dawn = gpu_dawn,
     .glfw = glfw,
-    .gamemode = gamemode,
 });
 
 var _module: ?*std.build.Module = null;

build.zig.zon

@@ -15,5 +15,9 @@
             .url = "https://github.com/hexops/mach-sysjs/archive/b71eb0531f337fcca5a2b245f595355260109a34.tar.gz",
             .hash = "12208b30f1d9c229d1e64483354610207c9aa06350a46558560b818d597800ed86e0",
         },
+        .mach_gamemode = .{
+            .url = "https://github.com/hexops/mach-gamemode/archive/936bcd7767bf7cae720d36d930599c20fdc87b1d.tar.gz",
+            .hash = "12203cb075bec68c8cb4cfa1337bc9dabe47f055e377d1b8144b2c21f9a2577efb07",
+        },
     },
 }