Fixed zig 0.16 support

Author: Blayung

src/androidbuild/apk.zig

@@ -363,16 +363,27 @@ fn doInstallApk(apk: *Apk) std.mem.Allocator.Error!*Step.InstallFile {
                     aapt2link.addArg("-A");
                     aapt2link.addDirectoryArg(asset_dir_path.source);
 
-                    var asset_dir = std.fs.cwd().openDir(asset_dir_path.source.cwd_relative, .{ .iterate = true }) catch |err| @panic(@errorName(err));
+                    const cwd = if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15) std.fs.cwd() else std.Io.Dir.cwd();
+
+                    var asset_dir = (
+                        if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15)
+                            cwd.openDir(asset_dir_path.source.cwd_relative, .{ .iterate = true })
+                        else
+                            cwd.openDir(b.graph.io, asset_dir_path.source.cwd_relative, .{ .iterate = true })
+                    ) catch |err| @panic(@errorName(err));
+
                     defer asset_dir.close();
 
                     var walker = try asset_dir.walk(b.allocator);
                     defer walker.deinit();
 
-                    while (walker.next() catch |err| @panic(@errorName(err))) |entry| {
-                        if (entry.kind == .file) {
-                            aapt2link.addFileInput(try asset_dir_path.source.join(b.allocator, entry.path));
-                        }
+                    while ((
+                        if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15)
+                            walker.next()
+                        else
+                            walker.next(b.graph.io)
+                    ) catch |err| @panic(@errorName(err))) |entry| {
+                        if (entry.kind == .file) aapt2link.addFileInput(try asset_dir_path.source.join(b.allocator, entry.path));
                     }
                 }
             }