New decorator/function "@cython.dataclasses.dataclass" and "cython.dataclasses.field()" to mark dataclasses and their fields.

Tries to match the interface provided by a regular dataclass as much as possible.
This means taking the types from the dataclasses module if available (so they match exactly) or a fallback Python version that just implements the core parts (executed with "PyRun_String()" in the C source).

Use of placeholders in generated "__init__" code means the code in the C file isn't hugely readable. Probably not a huge issue, but don't really see a way round that.

As part of this I've also also implemented a Cython version of "typing.ClassVar". Although really designed for use with dataclasses it behaves sensibly when used in types in a normal cdef class. This is worth documenting more thoroughly.

Closes https://github.com/cython/cython/issues/2903

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.

Closes https://github.com/cython/cython/issues/2636

See https://github.com/cython/cython/issues/4594#issuecomment-1022092245

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.

Move the option to "exclude" children from the tree traversal from the "VisitorTransform" class up to its parent "TreeVisitor" class.

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

Adapt to "exc_info" changes in CPython 3.11a4, where "->exc_type" and "->exc_traceback" are gone and now get inferred from "->exc_value".

Closes https://github.com/cython/cython/issues/4500

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

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

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

Disable the "dotted names not allowed" warning for include files, which may contain arbitrary directory paths and not just plain module names.

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

Closes https://github.com/cython/cython/issues/1214

Avoid misleading the C code formatter into adding an additional indentation level due to excess opening braces.

Avoid misleading the C code formatter into adding an additional indentation level due to an excess opening brace.

Make it easier to report errors from srctree tests by adding the last output to the reported AssertionError.

appveyor: Prevent the compiled Cython modules from being picked up during the build already by first compiling them completely before putting them into the source tree. On fork()-less Windows, late starting build processes could otherwise end up with partially compiled source trees.

Make the pyximport-pyimport tests more robust by testing that the file is compiled instead of looking at the "__file__" attribute.