Include python.exe copy of python3.13t.exe in Windows free-threaded distributions

Author: zanieb

cpython-windows/build.py

@@ -1662,6 +1662,15 @@ def build_cpython(
             os.environ,
         )
 
+        # Create a `python.exe` when using an alternative name, e.g., when
+        # freethreading is enabled the name is `python3.13t.exe`.
+        canonical_python_exe = install_dir / "python.exe"
+        if canonical_python_exe.exists():
+            shutil.copyfile(
+                python_exe,
+                canonical_python_exe,
+            )
+
         # We install pip by using pip to install itself. This leverages a feature
         # where Python can automatically recognize wheel/zip files on sys.path and
         # import their contents. According to
@@ -1811,7 +1820,6 @@ def build_cpython(
         }
 
         # Collect information from running Python script.
-        python_exe = out_dir / "python" / "install" / python_exe
         metadata_path = td / "metadata.json"
         env = dict(os.environ)
         env["ROOT"] = str(out_dir / "python")