Merge pull request #6006 from lukegb/tk-in-binary

Support Python distributions where _tkinter is compiled in

src/PIL/_tkinter_finder.py

@@ -5,10 +5,15 @@
 import warnings
 from tkinter import _tkinter as tk
 
-if hasattr(sys, "pypy_find_executable"):
-    TKINTER_LIB = tk.tklib_cffi.__file__
-else:
-    TKINTER_LIB = tk.__file__
+try:
+    if hasattr(sys, "pypy_find_executable"):
+        TKINTER_LIB = tk.tklib_cffi.__file__
+    else:
+        TKINTER_LIB = tk.__file__
+except AttributeError:
+    # _tkinter may be compiled directly into Python, in which case __file__ is
+    # not available. load_tkinter_funcs will check the binary first in any case.
+    TKINTER_LIB = None
 
 tk_version = str(tkinter.TkVersion)
 if tk_version == "8.4":