Allow directories to exist already.

upstream/build_tor_macos.py

@@ -42,8 +42,8 @@ def setup():
 def build():
     versions, jar_name = setup()
 
-    copytree('pre-out', os.path.join(BUILD_DIR, 'out'))
-    copytree('pre-clones', os.path.join(BUILD_DIR, 'git_clones'))
+    copytree('pre-out', os.path.join(BUILD_DIR, 'out'), dirs_exist_ok=True)
+    copytree('pre-clones', os.path.join(BUILD_DIR, 'git_clones'), dirs_exist_ok=True)
 
     build_arch(versions, 'aarch64')
     build_arch(versions, 'x86_64')