Also stop tracking the frozen manifest.

Author: ericsnowcurrently

.gitignore

@@ -121,9 +121,10 @@ Tools/msi/obj
 Tools/ssl/amd64
 Tools/ssl/win32
 
-# Python/frozen_modules/MANIFEST is enough to tell if the generated
-# files have changed.  See Tools/scripts/freeze_modules.py.
+# The frozen modules are always generated at build time.
 Python/frozen_modules/*.h
+# The manifest can be generated at any time with "make regen-frozen".
+Python/frozen_modules/MANIFEST
 
 # Two-trick pony for OSX and other case insensitive file systems:
 # Ignore ./python binary on Unix but still look into ./Python/ directory.