--- a/build/unix/build-clang/build-clang.py
+++ b/build/unix/build-clang/build-clang.py
@@ -52,17 +52,17 @@ def updated_env(env):
     os.environ.update(env)
     yield
     os.environ.clear()
     os.environ.update(old_env)
 
 
 def build_tar_package(tar, name, base, directory):
     name = os.path.realpath(name)
-    run_in(base, [tar, "-cjf", name, directory])
+    run_in(base, [tar, "-cJf", name, directory])
 
 
 def copy_dir_contents(src, dest):
     for f in glob.glob("%s/*" % src):
         try:
             destname = "%s/%s" % (dest, os.path.basename(f))
             shutil.copytree(f, destname)
         except OSError as e:
@@ -257,9 +257,9 @@ if __name__ == "__main__":
 
     if not is_darwin():
         stage2_inst_dir = stage2_dir + '/clang'
         build_and_use_libgcc(
             {"CC": cc + " %s" % extra_cflags,
              "CXX": cxx + " %s" % extra_cxxflags},
             stage2_inst_dir)
 
-    build_tar_package("tar", "clang.tar.bz2", stage2_dir, "clang")
+    build_tar_package("tar", "clang.tar.xz", stage2_dir, "clang")