See https://github.com/cython/cython/issues/3919

Avoid calling "PyErr_Clear()" in "__Pyx_CyFunction_get_is_coroutine()" if no error was raised (by our code).

* Avoid UtilityCode from cimport_from_pyx files
* Unique names for generated cfunc wrappers, avoid pxd pickle code
* Set .in_pxd on nodes prior to analyse_declarations

Fixes #3716
Fixes #3741
Fixes #3734

Mostly with the hope that the tests pass. Ideally we should support the most recent version.

Closes https://github.com/cython/cython/issues/2233

Even though the Python documentation states, that PyUnicode_KIND will return an int,
it actually returns a value of the underlying type of the PyUnicode_Kind enum.
This could be e.g. an unsigned int which can cause warnings about signed/unsigned comparisons.

Backported from 3dc2b9df
Partial fix for https://github.com/cython/cython/issues/3919

clang warns about dead code when an if-statement always evaluates to false. This warning can be silenced using an extra '()'.

The `test.support` has been split into sub-modules. Adapt `test_exceptions` (originally coped from CPython) for these changes.

Eliminate C compiler warnings by making the constness of the
char* pointers in the declarations in pycapsule.pxd match
the actual types of the PyCapsule_* functions.

Disable time_pxd test in Python 3.4

It uses features that are unavailable thus always fails

Test was introduced in https://github.com/cython/cython/pull/3767

Closes https://github.com/cython/cython/issues/4000

Closes https://github.com/cython/cython/issues/4000

It was broken in https://github.com/cython/cython/pull/3976 which added an additional error message.

Fixed e_decorators test

Warning message on cpdef variables (0.29.x)

Expose "long and overflow" cpython functions

These functions are available since Python 2.7.

Close #3980

Changed "declared after use" warning to error

* ENH: implement cpython/time.pxd
Co-authored-by: scoder <stefan_ml@behnel.de>