anchor.diff:        cc_flags = "-m32";
       } else if (arch == 'arm') {
         cc_flags = null;
  +    } else if (arch == 'arm64') {
  +      cc_flags = null;
       } else if (arch == 'mips') {
         cc_flags = "-EL";
       } else {
  
positive.code:       List arguments,
        Map<String, String> environmentOverrides) {
      var exec;
      if (isAndroid && arch == 'arm') {
        exec = "$buildDir/clang_x86/dart_bootstrap";
      } else {
        exec = "$buildDir/dart_bootstrap";
      }
  
negative.code:       Map<String, String> environmentOverrides) {
  
      var cc, shared;
      if (isAndroid) {
        var ndk = "third_party/android_tools/ndk";
        var triple;
        if (arch == "arm") {
          triple = "arm-linux-androideabi";
        } else if (arch == "arm64") {
          triple = "aarch64-linux-android";
        }
        var host;
        if (Platform.isLinux) {
          host = "linux";
        } else if (Platform.isMacOS) {
          host = "darwin";
        }
        cc = "$ndk/toolchains/$triple-4.9/prebuilt/$host-x86_64/bin/$triple-gcc";
        shared = '-shared';
      } else if (Platform.isLinux) {
        cc = 'gcc';
        shared = '-shared';
      } else if (Platform.isMacOS) {
  