Disable some plain Python (non Cython related) tests that fail in Py3.10 due to changed error messages.

Avoid "possible loss of data" warning in MSVC by adding redundant casts to code that gets discarded later.

Still requires the more conservative __index__ here rather than a possibly
truncating __int__ because this is used in a context where floating point
values should probably be treated specially.

This fixes Github issue #2752.

Repair coverage tests to make them work with coverage 6.1, which changed the HTML output format that the tests parse.

See https://github.com/python/cpython/pull/28968/8e5de40f90476249e9a2e5ef135143b5c6a0b512
which is part of implementing
https://bugs.python.org/issue35134
moved the header "longintrepr.h" into a sub-folder.
The notes on this change suggested to include "Python.h" instead.

docs: Use the Cython + IPython lexers that come with Pygments to avoid having to maintain our own ones.

Instead of __Pyx_SetTracing(), Profile.c now uses PyThreadState_EnterTracing() and PyThreadState_LeaveTracing(), which were added to Python 3.11.0a2:
https://github.com/python/cpython/pull/28542

When these functions are used, Cython no longer sets directly PyThreadState.cframe.use_tracing.

"PyUnicode_CompareWithASCIIString()" does not raise exceptions and takes a "const char*" as argument.

This was causing c++ classes in if-statements to crash.
Fixes #4348

Avoid copying unaligned 16-bit values since some platforms require them to be aligned. Use memcpy() instead to let the C compiler decide how to do it.

Closes https://github.com/cython/cython/issues/4343

Make a helper function in a C++ test correctly propagate exceptions so that it won't have to spit out compiler warnings.

Closes https://github.com/cython/cython/issues/4268

Closes https://github.com/cython/cython/issues/4214
Closes https://github.com/cython/cython/issues/2811

* Set "entry.qualified_name" for builtin types.
* Make sure we always have a correct "qualified_name" for all symtab Entry instances.

ALways mark the entry of generator expression functions as used. Because, why not, they probably are. And it avoids false warnings.
Fixes https://github.com/cython/cython/issues/1699

Don't access directly PyObject.ob_type and PyObject.ob_refcnt members.

Do not install Pythran in 0.29.x on travis since it is currently incompatible and unknown when it will work again.

Implement "gen.gi_frame" and "coro.cr_frame" attributes on generators and coroutines that return an inspectable (although otherwise dead) frame object.

Closes https://github.com/cython/cython/issues/2306

The utility code was generated at too late a stage, after the utility code from the pxd was merged into the pyx scope.

Fixes #1415

* Use the same fallback as for missing PEP-393 support.
* Prepare for "PyUnicode_READY()" and "PyUnicode_WCHAR_KIND" to be removed in Py3.12.
  See https://www.python.org/dev/peps/pep-0623/
* Avoid C compiler warnings about deprecated C-API functions in Py3.9+.

Closes https://github.com/cython/cython/issues/3925

Fix Python install script on appveyor: The URL path uses three digit Python versions, not just major.minor.

According to the docs, "/Od" is the default in MSVC, so in order to get it, it should be enough to clear CFLAGS.
Setting it generates warnings in Py3.9 on appveyor ("source file '"/Od"' ignored"), suggesting that the option is not recognised as such.
https://docs.microsoft.com/en-us/cpp/build/reference/od-disable-debug?view=msvc-160

Remove "PYTHONHOME" setting from embed-test since it seems to break the I/O encoding setup in (at least) Py3.8+ venvs.