PyInit_timezone() is declared as returning int, but it contains return statements without value.

From compiler output on Windows:

  timemodule.c
..\Modules\timemodule.c(1584): warning C4033: 'PyInit_timezone' must return a value [C:\py\cpython3.8\PCbuild\pythoncore.vcxproj]
..\Modules\timemodule.c(1589): warning C4033: 'PyInit_timezone' must return a value [C:\py\cpython3.8\PCbuild\pythoncore.vcxproj]
..\Modules\timemodule.c(1593): warning C4033: 'PyInit_timezone' must return a value [C:\py\cpython3.8\PCbuild\pythoncore.vcxproj]
c:\py\cpython3.8\modules\timemodule.c(1647): warning C4715: 'PyInit_timezone': not all control paths return a value [C:\py\cpython3.8\PCbuild\pythoncore.vcxproj]

Crap. My commit 503ce5c482cb267b0770bc46c315d5cf822bdca9 was supposed to fix on of the latest compiler warning in master, but I introduced a new warning :-( What a shame on me :-( I was too quick... PR 10861 should fix the new warning.

New changeset ab6614969301b238fcc27f43923a0189a57a2a3c by Victor Stinner in branch 'master':
bpo-35373: Fix PyInit_timezone() if HAVE_DECL_TZNAME is defined (GH-10861)
https://github.com/python/cpython/commit/ab6614969301b238fcc27f43923a0189a57a2a3c

Hum. By the way, PyInit_time() calls PyModule_AddObject() without checking for errors :-/

PyMODINIT_FUNC
PyInit_time(void)
{
    PyObject *m;
    m = PyModule_Create(&timemodule);
    if (m == NULL)
        return NULL;
    ...
    PyModule_AddObject(m, "struct_time", (PyObject*) &StructTimeType);
    ...
    return m;
}

It should have at least one final generic:

    if (PyErr_Occurred()) {
        return -1;
    }

New changeset 3bb150d8148e3cc08418077a58f43e064b9fde61 by Victor Stinner in branch 'master':
bpo-35373: Fix PyInit_time() error handling (GH-10865)
https://github.com/python/cpython/commit/3bb150d8148e3cc08418077a58f43e064b9fde61

New changeset 5eb78c75128187a36d8e983027632fa51cc2ff4d by Victor Stinner in branch '3.7':
[3.7] bpo-35373: Fix PyInit_timezone() error handling (GH-10864)
https://github.com/python/cpython/commit/5eb78c75128187a36d8e983027632fa51cc2ff4d

In Python 2.7, inittimezone() is simpler and so less likely to fail. I propose to leave Python 2.7 unchanged.

New changeset f455353bc0d195e092f09fec92ed16e9be02b7b1 by Miss Islington (bot) in branch '3.6':
[3.7] bpo-35373: Fix PyInit_timezone() error handling (GH-10864)
https://github.com/python/cpython/commit/f455353bc0d195e092f09fec92ed16e9be02b7b1