windows: normalize "Include" to "include"

See the inline comment and linked Python issue.

The misreporting of the include path is preventing PyOxidizer from
properly loading Windows distributions on case sensitive filesystems.

Author: indygreg

cpython-windows/generate_metadata.py

@@ -32,6 +32,12 @@
 root = os.environ["ROOT"]
 for name, path in sysconfig.get_paths().items():
     rel = os.path.relpath(path, root).replace("\\", "/")
+
+    # sysconfig on Windows reports the include path as "Include" but
+    # in reality it is "include." See https://bugs.python.org/issue41669.
+    # So we normalize accordingly.
+    rel = rel.replace("install/Include", "install/include")
+
     metadata["python_paths"][name] = rel
 
 with open(sys.argv[1], "w") as fh: