runtests: Print shard number also for each command in the EndToEnd test error output to make it easy to find in the logs.

runtests: print the shard number in front of the test name to show which was the last test in case it hangs.

Partially reverts https://github.com/cython/cython/commit/1027db04fb7c5bbfea2b9bcdfce0b1f384e26a93

By disabling "CYTHON_FAST_THREAD_STATE" and "CYTHON_USE_EXC_INFO_STACK"

I think this still leaves some breakage in Coroutines.c but it's enough of a fix that Cython succeeds in building itself. Therefore I think it's worth doing now even if it doesn't fix everything.

Related to https://github.com/cython/cython/issues/4500

Fix division-by-zero crash in tests when the C ompiler discards the computational body of a Cython coroutine.

Add a new command line option so that
$ cythonize -M foo.pyx
produces a file `foo.c.dep` with the dependencies of foo.pyx, in addition to `foo.c`.
Try to write relative paths as much as possible.

Backport of https://github.com/cython/cython/pull/4563

Make the test files that depend on "cythonarrayutil.pxi" compilable by themselves, without the search directory setup of the test runner.

Use "Py_ssize_t" instead of "int" for a node counter variable to avoid uselessly limiting its value range.

Disable parallel builds in the 0.29.x branch since they currently misbehave and fail in CI, trying to rebuild everything multiple times in parallel.

Cython incorrectly generated (optimised) range code for "for i in range(1,2,3,4)" as if it saw "for i in range(1,2,3)".
This PR deactivates this optimization when too many arguments are provided, to match the behavior of Python.
Original patch by Max Bachmann.

Closes https://github.com/cython/cython/pull/4550

Remove outdated warning about OpenMP < 3.0. Even the now-EOL Docker images for manylinux2010 had that.

Closes https://github.com/cython/cython/issues/4574

For PyPy3.8 (the current release is 7.3.7)

* PyPy<7.3.8 declares a struct with the last fields tp_finalize, tp_print, tp_pypy_flags
* PyPy>=7.3.8 will declare a struct with the last fields tp_finalize, tp_vectorcall, tp_print

PyPy3.9 (not yet released) will declare a struct with the last fields tp_finalize, tp_vectorcall, tp_pypy_flags

See https://foss.heptapod.net/pypy/pypy/-/issues/3618

Add "tp_pypy_flags" field to PyTypeObject struct when compiling in PyPy 6.0+ in order to avoid C compiler warnings about an uninitialised struct field.

This reverts commit f5aa00bb.

Closes https://github.com/cython/cython/issues/3938