Always call freeze_support() if sys.frozen is True

CHANGES.md

@@ -31,6 +31,9 @@
 
 <!-- Changes to how Black is packaged, such as dependency requirements -->
 
+- Executables made with PyInstaller will no longer crash when formatting several files
+  at once on macOS. Native x86-64 executables for macOS are available once again.
+  (#3275)
 - Hatchling is now used as the build backend. This will not have any effect for users
   who install Black with its wheels from PyPI. (#3233)
 - Faster compiled wheels are now available for CPython 3.11 (#3276)

src/black/__init__.py

@@ -1375,7 +1375,9 @@ def patch_click() -> None:
 
 
 def patched_main() -> None:
-    if sys.platform == "win32" and getattr(sys, "frozen", False):
+    # PyInstaller patches multiprocessing to need freeze_support() even in non-Windows
+    # environments so just assume we always need to call it if frozen.
+    if getattr(sys, "frozen", False):
         from multiprocessing import freeze_support
 
         freeze_support()