added tzdata package (#4697)

For zoneinfo to work, we need the tzdata package. This PR does that.

cpython/patches/0007-Warn-on-zoneinfo-without-tzdata.patch

@@ -0,0 +1,17 @@
+diff --git a/Lib/zoneinfo/_common.pyold b/Lib/zoneinfo/_common.py
+index 98cdfe37..75f8fd2b 100644
+--- a/Lib/zoneinfo/_common.py
++++ b/Lib/zoneinfo/_common.py
+@@ -11,6 +11,12 @@ def load_tzdata(key):
+     try:
+         return resources.files(package_name).joinpath(resource_name).open("rb")
+     except (ImportError, FileNotFoundError, UnicodeEncodeError):
++        import sys
++        if "tzdata" not in sys.modules:
++            raise ZoneInfoNotFoundError(
++                f"No time zone found with key {key}. \n"
++                " On Pyodide you must do pyodide.loadPackage('tzdata')"
++                " package before you use zoneinfo.")
+         # There are three types of exception that can be raised that all amount
+         # to "we cannot find this key":
+         #

docs/usage/wasm-constraints.md

@@ -46,6 +46,9 @@ Instead, it is better to load individual modules as needed using
   Pyodide includes some method stubs based on browser APIs:
   `webbrowser.open()`, `webbrowser.open_new()`, `webbrowser.open_new_tab()`.
 
+- zoneinfo: The zoneinfo package will only work if you install the timezone data using
+  the tzdata package (i.e. by calling `pyodide.loadPackage("tzdata")`)
+
 ### Synchronous HTTP requests support
 
 Packages for `urllib3` and `requests` are included in pyodide. In browser, these

packages/tzdata/meta.yaml

@@ -0,0 +1,13 @@
+package:
+  name: tzdata
+  version: "2024.1"
+  top-level:
+    - tzdata
+source:
+  url: https://files.pythonhosted.org/packages/65/58/f9c9e6be752e9fcb8b6a0ee9fb87e6e7a1f6bcab2cdc73f02bb7ba91ada0/tzdata-2024.1-py2.py3-none-any.whl
+  sha256: 9068bc196136463f5245e51efda838afa15aaeca9903f49050dfa2679db4d252
+about:
+  home: https://github.com/python/tzdata
+  PyPI: https://pypi.org/project/tzdata
+  summary: Provider of IANA time zone data
+  license: Apache-2.0